The implantation of cork oak (Quercus suber L) make use of herbicides: Preliminary results - Ortega, M; Villarroya, M; Montero, G; Chueca, M C; Garcia-Baudin, J M (CONGRESS 1997 - SOCIEDAD ESPANOLA DE MALHERBOLOGIA, PROCEEDINGS, 1997)
The response of cork oak (Quercus suber L.) to different rates of hexazinone, simazine and pendimetaline herbicides applied with a logaritmic sprayer, was studied. The effect on weeds of these herbicicles was also studied.
Keywords: Herbicides; Quercus suber L.

Influence of finishing diet on fatty acid profiles of intramuscular lipids, triglycerides and phospholipids in muscles of the Iberian pig. - Cava, R; Ruiz, J; López-Bote, C; Martín, L; García, C; Ventanas, J; Antequera, T (Meat science, 1997)
Thirty Iberian × Duroc pigs allotted in groups of ten animals were fed in three traditional different management systems ('Montanera' (MO), fed on acorns; 'Recebo' (RE), fed on acorns and a commercial diet; and 'Cebo' (CE), fed on a commercial diet). Masseter muscle was obtained to evaluate the influence of management system on fatty acid (FA) composition of lean. The FA composition of the intramuscular total lipids, triglyceride (TG) and phospholipid (PL) fractions was evaluated. Muscle from MO pigs had greater quantities of monounsaturated fatty acids (MUFA) in the total lipids, triglyceride and phospholipid fractions than the other feedings. The percentage of saturated fatty acids (SFA) of i.m. total lipids and TGs increased (P < .05) with duration of feeding on RE and CE, from 35.13-35.10% in MO pigs to 37.47-37.84% in RE pigs and 39.98-41.11% in CE pigs. PLs from RE and CE pigs contained more C(18:2) and C(20:4) and less C(18:1) than MO pigs.
Keywords: Fatty acid profile (PG); Feeding system; iberian pig

INFLUENCIA DE LA SUPERFICIE DISPONIBLE Y DEL TAMAÑO DEL REBAÑO EN LOS PASTOS MEJORADOS Y EN LA PRODUCCIÓN DE LA DEHESA EN EL SO - Olea, L; Paredes, J (Pastos, 1997)
Los métodos de mejora de pastos semiáridos mediterráneos del SO de la Penínsu- la Ibérica basados en la aportación de P, en el fomento de las leguminosas y en el pasto- reo continuo han sido investigados ampliamente, siempre en pequeñas superficies. Era pues necesario comprobar su utilización en dimensiones de parcelas y "rebaños" reales de explotación. Sobre pasto sembrado con variedades de trébol subterráneo y pasto natural fertili- zado en dos localizaciones (Oliva de la Frontera en el SO de Badajoz y Navalmoral de la Mata en el NE de Cáceres) se han estudiado estas mejoras aplicadas a dimensiones de parcelas y rebaños que van de una ha y 3-4 ovejas a 30 ha y 90-120 ovejas, durante cinco años. Los resultados en producciones vegetales, semilla en el suelo para su germinación y composición botánica permiten afirmar que no existen grandes diferencias entre estas superficies y número de animales, incluso en años en los que hubo una importante se- quía y las suplementaciones medias llegaron a ser hasta del 58% del tiempo en Oliva. En resultados de producción animal aparecen mayores diferencias a favor de su- perficies y rebaños menores siempre hasta parcelas de 15 ha y 45-60 animales, debido a la influencia del manejo de los animales pero no del pasto. En general puede decirse que esta tecnología de mejora es aplicable a tamaños de parcelas y rebaños viables en condiciones reales de explotación de la dehesa
Keywords: pastos mediterráneos; sistemas extensivos sostenibles; trébol subterráneo

Influencia de los tratamientos selvícolas destinados a optimizar el desarrollo de QUERCUS ILEX SSP. BALLOTA BAJO LA CUBIERTA DE PINARES DE REPOBLACIÓN - ALVAREZ LINAREJOS, LAURA; ALEJANO MONGE, REYES; MADRIGAL COLLAZO, ALBERTO MARTÍNEZ MONTES, ENRIQUE; RApp ARRARÁS, ÍGOR (II Congreso Forestal Español, 1997)
Results about variables with important influence in the evolution of holm oak seedlings planted under pine trees covert, are shown in this work. These results come as part of a large experience placed in the Filabres Mountains, in Almería, Spain. Relations among the answer of the holm oaks studied, the pine forest -in which different intensity thinnings has been done- and different soil variables -meassured in the field plots- are searched.
Keywords: broadleaves sylviculture; Holm oak; mixed forest; oak sylviculture; thinnings

Influencia del tamaño de bellota y del régimen de riego en la calidad de planta de alcornoque cultivada en vivero - Pardos Mínguez, M.; Cañellas, I.; Bachiller, A. (II Congreso Forestal Español, 1997)
The effect of three acorn sizes (small, medium and large, 2.5, 5 and 8.8 g mean fresh weight, respectively) and two irrigation regimes (Rl=2R2) in the growth of cork oak containerized (Forest Pot 300) seedlings was studied. The seedlings were grown in the nursery for one year.The results showed the influence of the acorn size on caliper, root volume, shoot, root and acorn dry weights, leaf area, leaf weight ratio (L WR), leaf area ratio (LAR), midday water potential and transpiration. Irrigation was statistically significant for height and totalleaf area. Water potential reached less than -2 MPa in July. This fact reveals the adaptation of the species to drought.
The following values have no corresponding Zotero field: periodical: II Congreso Forestal Español
Keywords: acorn size; irrigation; Quercus suber; seedling quality

Influencia del tamaño de bellota y del régimen de riego en la calidad de planta de alcornoque cultivada en vivero - Pardos Mínguez, M; Cañellas, I; Bachiller, A (II Congreso Forestal Español, 1997)
The effect of three acorn sizes (small, medium and large, 2.5, 5 and 8.8 g mean fresh weight, respectively) and two irrigation regimes (Rl=2R2) in the growth of cork oak containerized (Forest Pot 300) seedlings was studied. The seedlings were grown in the nursery for one year.The results showed the influence of the acorn size on caliper, root volume, shoot, root and acorn dry weights, leaf area, leaf weight ratio (L WR), leaf area ratio (LAR), midday water potential and transpiration. Irrigation was statistically significant for height and totalleaf area. Water potential reached less than -2 MPa in July. This fact reveals the adaptation of the species to drought.
Keywords: acorn size; irrigation; Quercus suber; seedling quality

INFLUENCIA DEL TAMAÑO DE LA SEMILLA Y DIFERENTES DOSIS DE FERTILIZACION SOBRE EL CRECIMIENTO Y SUPERVIVENCIA EN CAMPO DE CUATRO ESPECIES FORESTALES - OCAÑA BUENO, L; DOMÍNGUEZ LERENA, S; CARRASCO MANZANO, I; PEÑUELAS RUBIRA, J L; HERRERO SIERRA, N (II Congreso Forestal Español, 1997)
The effect of different fertilization doses on the growth in nursery and the field performance were assessed in Q.ilex, P.pinea, P.pinaster and P.sylvestris, wich differ in their seed size. Growth in nursery and results in the field showed marcked differences between fertilized and unfertilized treatments. Smaller seed species are more dependent on fertilization than larger seed species.
Keywords: fertilization; P.pinaster y P.sylvestris; P.pinea; Q.ilex; Seed size

Interannual variations of nutrient concentrations in botanical fractions from extensively managed grasslands - Ruano-Ramos, A (Animal Feed Science …, 1997)
We studied interannual variations in the concentrations of N, P, K, Ca, Mg, Na, Mn, Fe, Cu, and Zn in botanical fractions from semi-natural grassland in central-western Spain. Herbage samples were collected at the ripening stage at the end of May over a 4-year period (1987, 1988, 1989 and 1991) and classified into: grasses, legumes and forbs. There was an increase in N, P and K contents from 1987 until 1991. The interannual differences in Ca, Mn, Cu and Zn concentra- tions showed no clear trends. However, the sampling year had no significant effect on Mg and Na contents. Grasses generally exhibited significant lower nutrient contents than legumes and forbs. Forbs had N, Ca, Mg and Cu concentrations midway between those of grasses and legumes, and higher P, K, Fe and Zn contents than legumes. The P, Mg, and Na contents in the three botanical fractions were inadequate for feeding livestock. However, the K, Mn, and Fe contents in the three botanical groups and the Ca, Cu, and Zn contents in legumes and forbs were within recommended ranges for cattle. The N contents were only adequate in legumes. These and forbs appear to be most suitable for cattle feeding on account of their mineral contents
Keywords: correlation; grassland; Interannual variations; Mineral content

Isoprenoid emission of oak species typical for the Mediterranean area: Source strength and controlling variables - Steinbrecher, Rainer; Hauff, Karin; Rabong, Richard; Steinbrecher, Jutta (Atmospheric Environment, 1997)
easurements of isoprenoid emission on five Mediterranean oak species in the field revealed that Quercu.s frainetto, Quercus petraea and Quercus pubescens are strong emitters of isoprene. In contrast Quercus cerris and Quercus suber emitted no significant amounts of isoprene and monoterpenes. For Q. pubenscens and Q. frainetto median emission factors of 16.68 nmoIm-2s-1 (86.06 pgg-’ dw h-‘) and 30.72 nmolrn-2s-1 (133.95 pgg-’ dw h-l) were calculated, respectively. The 25 to 75 percentiles span of the emission factor data sets ranged from - 53% to + 56% of the median values. Light and temperature are the main controlling factors for isoprene emission. The influence of other environmental and plant physiological parameters on the isoprene emission is discussed. The “Guenther” emission algorithm is able to predict the daily maximum of the isoprene emission within the plant specific uncertainty range. However, the morning increase and the afternoon drop in the isoprene emission is not well parameterized. On the basis of process oriented models for the synthesis of isoprene in plants, a further reduction in the uncertainty may be achieved resulting in a more reliable prediction of short-time variation in isoprene emission
Keywords: biogenic voc; Emission factors; isoprene; Monoterpene; Quercus

Isoprenoid emission of oak species typical for the Mediterranean area: Source strength and controlling variables - Steinbrecher, Rainer; Hauff, Karin; Rabong, Richard; Steinbrecher, Jutta (Atmospheric Environment, 1997)
easurements of isoprenoid emission on five Mediterranean oak species in the field revealed that Quercu.s frainetto, Quercus petraea and Quercus pubescens are strong emitters of isoprene. In contrast Quercus cerris and Quercus suber emitted no significant amounts of isoprene and monoterpenes. For Q. pubenscens and Q. frainetto median emission factors of 16.68 nmoIm-2s-1 (86.06 pgg-’ dw h-‘) and 30.72 nmolrn-2s-1 (133.95 pgg-’ dw h-l) were calculated, respectively. The 25 to 75 percentiles span of the emission factor data sets ranged from - 53% to + 56% of the median values. Light and temperature are the main controlling factors for isoprene emission. The influence of other environmental and plant physiological parameters on the isoprene emission is discussed. The “Guenther” emission algorithm is able to predict the daily maximum of the isoprene emission within the plant specific uncertainty range. However, the morning increase and the afternoon drop in the isoprene emission is not well parameterized. On the basis of process oriented models for the synthesis of isoprene in plants, a further reduction in the uncertainty may be achieved resulting in a more reliable prediction of short-time variation in isoprene emission
Keywords: biogenic voc; Emission factors; isoprene; Monoterpene; Quercus

A landscape in transition: an historical perspective on a Spanish latifundist farm - Pérez, A S; Remmers, G G A (Agriculture, ecosystems & environment, 1997)
An agricultural landscape, as a social construction, is not static, but a reflection of the balance of social forces which influence the way in which the natural resources of the site are combined. To understand and evaluate the current configuration of a landscape, and to define and understand criteria according to which a future landscape may be designed, it is necessary to analyse its historical construction. In this paper we follow these steps, taking as a point of reference a farm in one of the most important agricultural regions of Spain, the Guadalquivir river valley in Andalucla. This region stands out for its high production potential, social inequity and environmental degradation. The paper describes global changes in the use of the land in this river valley over the past 3 centuries, and uses aerial photographs from 1956 and 1990 to outline changes on the 1150-ha Los Humosos farm, recently granted to a co-operative of land labourers after years of struggle for land. Through this change in tenure the criteria 'control' and 'distribution of benefits' are achieved. Nine other criteria derived from the historical analysis were used to compare four different farm design scenarios through multi-criteria programming, which was preceded by an assessment of the biogeophysical characteristics of the land. However, this appeared to be insufficient to cope with essential criteria such as landscape architecture and biodiversity, because minor landscape elements were neglected which are important starters for the design of an ecological infrastructure. Water, a problematic resource in Mediterranean agriculture, paradoxically turned out to be an important characteristic of these landscape elements. From historical, ecological and social perspectives, new proposals for farm landscape design must necessarily and radically break with the recent past. It appears, however, that to produce agricultural landscapes of quality in the Guadalquivir river valley would involve tough social struggle, that nonetheless is found to use the margins left over by the dominant socio-economic, cultural and political structures. Finally, an agro-ecological option is proposed as a transitional design
Keywords: ecological agriculture; History; land labourers; landscape; Mediterranean; Spain; water

Landscape structure and breeding bird distribution in a sub-Mediterranean agro-ecosystem - Farina, Almo (Landscape Ecology, 1997)
Richness, abundance and distribution of birds were investigated in the Aulella watershed, a mountainous area of 300 km2 , located in the extreme northwestern corner of Tuscany, Italy in spring and summer, 1995. The study area encompasses five vegetation types (from Mediterranean maqui to upland beech forest) and three main land use categories (woodlands, mixed cultivated + urban areas, montane prairies). The recent history of land abandonment in the study area has produced a rapid expansion of shrubland and woodland, reducing cultivated areas to small patches interspersed in a woodland matrix. Richness, abundance and distribution of birds recorded at 414 points, randomly selected along secondary roads, and located using a Global Positioning System (GPS), were compared with topography, vegetation type and land use in a Geographic Information Systems (GIS) with a grid cell resolution of 200 × 200 m. Bird richness (55 species in all) and abundance are correlated: (a) negatively with the increasing altitude and increasing distance from cultivated areas; (b) positively with the increasing distance from woodlands and mountain prairies. Slope orientation appears to have a negligible effect on bird assemblages. Bird richness and abundance are significantly correlated with vegetation type. Cultivated areas support the highest bird richness and abundance that increase with patch size of the cultivated areas. Local extinction and/or reduction in within-species abundance of birds are expected to continue if the process of land abandonment continues.
Keywords: aulella watershed; geographic information systems; global positioning system; sub-mediterranean agro-ecosystem; tuscany

Landscape structure and breeding bird distribution in a sub-Mediterranean agro-ecosystem - Farina, Almo (Landscape Ecology, 1997)
Richness, abundance and distribution of birds were investigated in the Aulella watershed, a mountainous area of 300 km2 , located in the extreme northwestern corner of Tuscany, Italy in spring and summer, 1995. The study area encompasses five vegetation types (from Mediterranean maqui to upland beech forest) and three main land use categories (woodlands, mixed cultivated + urban areas, montane prairies). The recent history of land abandonment in the study area has produced a rapid expansion of shrubland and woodland, reducing cultivated areas to small patches interspersed in a woodland matrix. Richness, abundance and distribution of birds recorded at 414 points, randomly selected along secondary roads, and located using a Global Positioning System (GPS), were compared with topography, vegetation type and land use in a Geographic Information Systems (GIS) with a grid cell resolution of 200 × 200 m. Bird richness (55 species in all) and abundance are correlated: (a) negatively with the increasing altitude and increasing distance from cultivated areas; (b) positively with the increasing distance from woodlands and mountain prairies. Slope orientation appears to have a negligible effect on bird assemblages. Bird richness and abundance are significantly correlated with vegetation type. Cultivated areas support the highest bird richness and abundance that increase with patch size of the cultivated areas. Local extinction and/or reduction in within-species abundance of birds are expected to continue if the process of land abandonment continues.
Keywords: aulella watershed; geographic information systems; global positioning system; sub-mediterranean agro-ecosystem; tuscany

The late-glacial at Lac de Creno (Corsica, France): a key site in the western Mediterranean basin - REILLE, M; Gamisans, J; De Beaulieu, J.-L.; ANDRIEU, V (New Phytologist, 1997)
The lower part (460–650 cm) of a lacustrine sequence from Lac de Creno, Corsica (1310 m) is analysed on the basis of 68 pollen spectra and with the support of 10 14C dates (including nine A.M.S. dates). This sequence, which extends from the end of the Würm to the beginning of the Postglacial, reveals a complete late-glacial. The absence of forest dynamics during the late glacial Interstadial in Corsica is a real mystery. Pollen data clearly suggest that Pinus laricio (=Pinus nigra Arnold ssp. laricio Maire) and perhaps other tree species did not exist in Corsica at that time.
Keywords: Lac de Creno (Corsica); Late-glacial; pollen spectra; western Mediterranean basin

Leaf morphology and leaf chemical composition in three Quercus (Fagaceae) species along a rainfall gradient in NE Spain - Castro-Díez, P. (Trees-Structure and …, 1997)
mLeaf features were examined in three Quercus species (Q. coccifera, Q. ilex and Q. faginea) along a steep rainfall gradient in NE Spain. The analyzed leaf traits were area, thickness, density, specific mass, leaf concentration of nitrogen, phosphorous, lignin, cellulose and hemicellulose, both on a dry weight basis (Nw, Pw, Lw, Cw, Hw) and on an area basis (Na, Pa, La, Ca, Ha). These traits were regressed against annual precipitation and correlated with each other, revealing different response patterns in the three species. Q. faginea, a deciduous tree, did not show any significant correlation with rainfall. In Q. coccifera, an evergreen shrub, Nw, Na, Lw, La and Ca increased with higher annual rainfall, while Hw decreased. In Q. ilex, an evergreen tree, leaf area, Pw and Lw increased with precipitation, whereas specific leaf mass, thickness and Ha showed the reverse response. Correlations between the leaf features revealed that specific mass variation in Q. faginea and Q. coccifera could be explained by changes in leaf density, while in Q. ilex specific leaf mass was correlated with thickness. Specific leaf mass in the three species appeared positively correlated with all the chemical components on a leaf area basis except with lignin in Q. ilex and with P in Q. ilex and Q. faginea. In these two tree species Pw showed a negative correlation with specific leaf mass. It is suggested that each species has a different mechanism to cope with water shortage which is to a great extent related to its structure as a whole, and to its habit.
Keywords: environmental gradient; Leaf fibre content; leaf morphology; Leaf nutrient content; Mediterranean climate

Leaf morphology and leaf chemical composition in three Quercus (Fagaceae) species along a rainfall gradient in NE Spain - Castro-Diez, P (Trees-Structure and …, 1997)
mLeaf features were examined in three Quercus species (Q. coccifera, Q. ilex and Q. faginea) along a steep rainfall gradient in NE Spain. The analyzed leaf traits were area, thickness, density, specific mass, leaf concentration of nitrogen, phosphorous, lignin, cellulose and hemicellulose, both on a dry weight basis (Nw, Pw, Lw, Cw, Hw) and on an area basis (Na, Pa, La, Ca, Ha). These traits were regressed against annual precipitation and correlated with each other, revealing different response patterns in the three species. Q. faginea, a deciduous tree, did not show any significant correlation with rainfall. In Q. coccifera, an evergreen shrub, Nw, Na, Lw, La and Ca increased with higher annual rainfall, while Hw decreased. In Q. ilex, an evergreen tree, leaf area, Pw and Lw increased with precipitation, whereas specific leaf mass, thickness and Ha showed the reverse response. Correlations between the leaf features revealed that specific mass variation in Q. faginea and Q. coccifera could be explained by changes in leaf density, while in Q. ilex specific leaf mass was correlated with thickness. Specific leaf mass in the three species appeared positively correlated with all the chemical components on a leaf area basis except with lignin in Q. ilex and with P in Q. ilex and Q. faginea. In these two tree species Pw showed a negative correlation with specific leaf mass. It is suggested that each species has a different mechanism to cope with water shortage which is to a great extent related to its structure as a whole, and to its habit.
Keywords: environmental gradient; Leaf fibre content; leaf morphology; Leaf nutrient content; Mediterranean climate

Linking individual foraging behavior and population spatial distribution in patchy environments: a field example with Mediterranean blue tits - Pulido, F J; Diaz, M (Oecologia, 1997)
In spite of recent theoretical interest, few field studies have addressed the links between individual behavioral decisions and population distribution. This work analyzes the foraging behavior of individuals and the spatial distribution of a population of blue tits (Parus caeruleus) just before the main breeding season, when blue tit foraging was not affected by central-place or flocking behaviors. The study was carried out in open holm oak Quercus ilex woodlands (dehesas) that are patchy for canopy-foraging birds because of the scattered arrangement of trees. Residence time on each tree was not correlated either with previous flight time or with prey abundance in trees. Flight distances between trees were larger than average distances estimated in random samples of holm oaks taken close to foraging birds. Trees were not selected by birds on the basis of their expected energy costs and rewards. Bird abundance was not related to food availability in trees or to tree size across dehesas. However, bird abundance was strongly correlated with tree density and with the availability of tree holes for nesting, to the extent that the proportion of tits matched the proportions of both tree abundance and hole abundance across study plots. Overall, neither the behavior of individuals nor the distribution of the population of blue tits corresponded with food resources, which appeared superabundant; instead, tits appeared to behave and be distributed according to the distribution of structural resources such as trees and tree holes for nesting.
Keywords: Food abundance; Habitat structure; Individual foraging behavior; Parus caeruleus; Population distribution

Liquid medium culture of Quercus suber L somatic embryos comparation between liquid and solid culture and among different growing media - Garcia, G.; Fernandez-Galiano, E.; Mauri, P. V. (HORTICULTURAL BIOTECHNOLOGY IN VITRO CULTURE AND BREEDING, 1997)
The objective of this study was to overcome two of the limiting factors of the standard culture protocol, in agar solidified medium, of cork oak somatic embryos: the low rate of mature embryos obtained, and the high labor and time consumed. First experiment. Immature somatic embryos of 2 mm. length were cultured for 30 days in four different growing media: 1/2SH{*}, SH{*}, 2xSH{*} and MS, both in solid and liquid phase. Higher fresh weights were detected, in every media, using liquid culture. In relation to developmental pattern, liquid culture in 1/2SH{*} has demonstrated to be the most effective combination for the first developmental stages producing lower percentages of secondary embryogenesis. Second experiment. Immature somatic embryos were cultured for 15 days in liquid 1/2SH{*} and transferred to the four different media. The richest media were shown to be more appropriated for the maturation stage giving higher rates of mature embryos.
The following values have no corresponding Zotero field: periodical: HORTICULTURAL BIOTECHNOLOGY IN VITRO CULTURE AND BREEDING issue: 447 pub-location: PO BOX 500, 3001 LEUVEN 1, BELGIUM
Keywords: Cork oak; liquid culture; mature embryos

Liquid medium culture of Quercus suber L somatic embryos comparation between liquid and solid culture and among different growing media - Garcia, G; Fernandez-Galiano, E; Mauri, P V (HORTICULTURAL BIOTECHNOLOGY IN VITRO CULTURE AND BREEDING, 1997)
The objective of this study was to overcome two of the limiting factors of the standard culture protocol, in agar solidified medium, of cork oak somatic embryos: the low rate of mature embryos obtained, and the high labor and time consumed. First experiment. Immature somatic embryos of 2 mm. length were cultured for 30 days in four different growing media: 1/2SH{*}, SH{*}, 2xSH{*} and MS, both in solid and liquid phase. Higher fresh weights were detected, in every media, using liquid culture. In relation to developmental pattern, liquid culture in 1/2SH{*} has demonstrated to be the most effective combination for the first developmental stages producing lower percentages of secondary embryogenesis. Second experiment. Immature somatic embryos were cultured for 15 days in liquid 1/2SH{*} and transferred to the four different media. The richest media were shown to be more appropriated for the maturation stage giving higher rates of mature embryos.
Keywords: Cork oak; liquid culture; mature embryos

Low Molecular Weight Polyphenols in Cork of Quercus suber - Conde, Elvira; Cadahía, Estrella; García-Vallejo, María Concepción; Fernández de Simón, Brígida; González Adrados, José Ramón (Journal of Agricultural and Food Chemistry, 1997)
Low molecular weight polyphenols were studied by HPLC in samples of cork from different trees of Spanish Quercus suber and at different industrial processing stages. Gallic, protocatechuic, vanillic, caffeic, ferulic, and ellagic acids; protocatechuic, vanillic, coniferylic, and sinapic aldehydes, and aesculetin and scopoletin were identified and quantified. Ellagic acid was the main component in all of the samples, followed by the rest of the phenolic acids, which had very much lower concentrations. Four components, caffeic, ferulic, and protocatechuic acids and vanillin, were selected as those that provided the greatest differences among the trees studied. In relation to the four industrial processing stages considered, marked differences were observed between the first two stages, stripping and first rest, and the stages after boiling. In this case, the discriminant variables were coniferaldehyde, sinapaldehyde, and ellagic acid. Keywords: Quercus suber; cork; polyphenols; phenolic acids and aldehydes; coumarins; high-performance liquid chromatography
doi: 10.1021/jf960486wdoi: 10.1021/jf960486wThe following values have no corresponding Zotero field: publisher: American Chemical Society
Keywords: Cork; coumarins; high- performance liquid chromatography; phenolic acids and aldehydes; polyphenols; Quercus suber

Low Molecular Weight Polyphenols in Cork of Quercus suber - Conde, Elvira; Cadahía, Estrella; García-Vallejo, María Concepción; Fernández de Simón, Brígida; González Adrados, José Ramón (Journal of Agricultural and Food Chemistry, 1997)
Low molecular weight polyphenols were studied by HPLC in samples of cork from different trees of Spanish Quercus suber and at different industrial processing stages. Gallic, protocatechuic, vanillic, caffeic, ferulic, and ellagic acids; protocatechuic, vanillic, coniferylic, and sinapic aldehydes, and aesculetin and scopoletin were identified and quantified. Ellagic acid was the main component in all of the samples, followed by the rest of the phenolic acids, which had very much lower concentrations. Four components, caffeic, ferulic, and protocatechuic acids and vanillin, were selected as those that provided the greatest differences among the trees studied. In relation to the four industrial processing stages considered, marked differences were observed between the first two stages, stripping and first rest, and the stages after boiling. In this case, the discriminant variables were coniferaldehyde, sinapaldehyde, and ellagic acid. Keywords: Quercus suber; cork; polyphenols; phenolic acids and aldehydes; coumarins; high-performance liquid chromatography
doi: 10.1021/jf960486w
Keywords: Cork; coumarins; high- performance liquid chromatography; phenolic acids and aldehydes; polyphenols; Quercus suber

Mate guarding in the spotless starling (Sturnus unicolor): Timing and duration pattern in intermediate breeding pairs - Deceuninck, B; Peris, S J; Calvo, J M; Pascual, J A; DelaCruzCardiel, P J (FOLIA ZOOLOGICA, 1997)
Mate guarding behaviour in the spotless starling Sturnus unicolor, a colonially breeding passerine was observed in five focal pairs of a nestbox colony in a Spanish `'dehesa'' (extensive pastured helm oak wood) in 1993. Daily observations were performed since the day of pair formation. Escorting behaviour began 4 days prior to laying and declined sharply between the 2 and 3 days of the laying period. Males followed their females more than the reverse, and spent more than 90% of time in the colony with the female during her fertile period. When escorting the females, males actively chased off other males to prevent them appproaching their mate. While males escorted females during fertile period up to 100% of times when they left colony, females came back to colony without their mate nearly 30% of times, showing that females succeeded in escaping their mate Vigilance when moving outside the colony. These results suggest that males guard in aim to keep other males away from their female, but also to keep females from approaching other males. Most of the observed copulations occurred during the guarding period. No extra-pair copulations (EPC) were witnessed between individuals of breeding pairs during the study time. One attempt of EPC occurred between a male of focal pair and a female of non-focal unstable pair. Nestbox occupation by unstable pairs and the shortness of time separating pair formation and laying in intermediate breeding pairs are discussed.
Keywords: intermediate clu; male behaviour; Sturnus unicolor

Mate guarding in the spotless starling (Sturnus unicolor): Timing and duration pattern in intermediate breeding pairs - Deceuninck, B.; Peris, S. J.; Calvo, J. M.; Pascual, J. A.; DelaCruzCardiel, P. J. (FOLIA ZOOLOGICA, 1997)
Mate guarding behaviour in the spotless starling Sturnus unicolor, acolonially breeding passerine was observed in five focal pairs of a nestbox colony in a Spanish `'dehesa'' (extensive pastured helm oak wood) in 1993. Daily observations were performed since the day of pair formation. Escorting behaviour began 4 days prior to laying and declined sharply between the 2 and 3 days of the laying period. Males followed their females more than the reverse, and spent more than 90% of time in the colony with the female during her fertile period. When escorting the females, males actively chased off other males to prevent them appproaching their mate. While males escorted females during fertile period up to 100% of times when they left colony, females came back to colony without their mate nearly 30% of times, showing that females succeeded in escaping their mate Vigilance when moving outside the colony. These results suggest that males guard in aim to keep other males away from their female, but also to keep females from approaching other males. Most of the observed copulations occurred during the guarding period. No extra-pair copulations (EPC) were witnessed between individuals of breeding pairs during the study time. One attempt of EPC occurred between a male of focal pair and a female of non-focal unstable pair. Nestbox occupation by unstable pairs and the shortness of time separating pair formation and laying in intermediate breeding pairs are discussed.
The following values have no corresponding Zotero field: pub-location: KVETNA 8, BRNO, CZECH REPUBLIC 603 65 publisher: INST VERTEBRATE ZOOLOGY
Keywords: male behaviour; Sturnus unicolor; intermediate clu

Medicinal plants used in the Barros Area, Badajoz Province, Spain. - Vázquez, F M; Suárez, M A; Pérez, A (Journal of ethnopharmacology, 1997)
A study of the wild and cultivated medicinal plants used in the Barros Area (southern Spain) is reported, 48 plants distributed among 20 different families are used in the treatment of various human diseases. The use of Bellis annua L. Centaurea ornata Wild., Leuzea conifera (L.) DC., Pulicaria paludosa Link and Asparagus aphyllus L. is reported.
From Duplicate 2 (Medicinal plants used in the Barros Area, Badajoz Province, Spain. - Vázquez, F M; Suarez, M a; Pérez, A)
Keywords: Data Collection; Humans; Medicinal; Medicinal plants; Medicinal: classification; Medicine; Phytotherapy; Plants; southern Spain; Spain; Structure-Activity Relationship; Traditional; Traditional phytotherapy

Medicinal plants used in the Barros Area, Badajoz Province, Spain. - Vázquez, F. M.; Suarez, M. a; Pérez, A. (Journal of ethnopharmacology, 1997)
A study of the wild and cultivated medicinal plants used in the Barros Area (southern Spain) is reported, 48 plants distributed among 20 different families are used in the treatment of various human diseases. The use of Bellis annua L. Centaurea ornata Wild., Leuzea conifera (L.) DC., Pulicaria paludosa Link and Asparagus aphyllus L. is reported.
From Duplicate 2 (Medicinal plants used in the Barros Area, Badajoz Province, Spain. - Vázquez, F M; Suarez, M a; Pérez, A)From Duplicate 2 (Medicinal plants used in the Barros Area, Badajoz Province, Spain. - Vázquez, F M; Suarez, M a; Pérez, A)The following values have no corresponding Zotero field: accession-num: 9032619
Keywords: Data Collection; Humans; Medicinal; Medicinal plants; Medicinal: classification; Medicine; Phytotherapy; Plants; southern Spain; Spain; Structure-Activity Relationship; Traditional; Traditional phytotherapy

Micoflora asociada al alcornoque - MuÑoz LÓPEZ, C; COBOS SUÁREZ, P; MARTÍNEZ SAAVEDRA, G; SOLDEVILLA PUGA, C; DÍAZ LLORENTE, M (II Congreso Forestal Español, 1997)
This proyect intends both to reflect a synthesis of the results obtained in the study of the fungi related to Q. suber L., first in the Parque Natural de los Alcornocales (Cádiz), and then in other areas of Spain, and to highlight the rol of especific fungi detected in the group of all mycetes which are described in the same work
Keywords: Armillaria mellea; diplodia mutila; Hypoxylon mediterraneum; mycology flora; phytophthora cinnamomi; Quercus suber

Mineralogical composition of African dust delivered by red rains over northeastern Spain - Avila, a; QueraltMitjans, I; Alarcon, M (JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 1997)
The African dust deposition, mineralogy, source regions, and influence on rain chemistry were analyzed for a site in the Montseny mountains (Catalonia, northeastern Spain) for the period August 1, 1983, through August 1, 1994. Dust deposition was highly variable: two events (collected on November 9-11, 1984, and March 22-25, 1991) accounted for 62% of the total dust input in the 38 red rain events recorded in the period. The average annual dust deposition was 5.3 g m(-2) (SE 2.6). Three source regions in the African continent were identified with back trajectory analysis: (1) Western Sahara, (2) Moroccan Atlas, and (3) Central Algeria. Events from the Moroccan Atlas predominated in terms of number of events, amount of rainfall, and dust deposition. The meteorological situations during red rains were identified: Western Sahara events occurred principally with a depression at high latitudes (50 degrees N) forming a trough in the North Atlantic, Moroccan Atlas events occurred with a depression in front of Portugal, and events from central Algeria were associated with a depression over Spain or North Africa. By order of abundance (median of n=13) the minerals identified in the dust by X ray diffraction were as follows: illite > quartz > smectite > palygorskite > kaolinite > calcite > dolomite > feldspars. Differences in mineralogy between source regions were significant for smectite, kaolinite, quartz, and dolomite. Smectite and kaolinite content was highest in the Algerian events, while quartz and dolomite content was lowest. Events from the Moroccan Atlas had the lowest smectite and kaolinite. The red rain soluble chemistry was clearly influenced by the dissolution of calcite (high alkalinity, calcium concentration and basic pH) and by marine components (high Na+, Cl- and Mg+2 concentrations). Because of the very alkaline character of red rains they had a strong weight on the annual mean pH of rainwater. This was reflected by the significant relationship (r=0.71, p<0.01) between the percentage of annual precipitation as red rain and annual mean precipitation pH. Red rains provided 25-45% of the annual dissolved input of the major ions in precipitation and 34% of the calcium required for helm oak (Quercus ilex L.) forest growth at the study site.
APS
Keywords: Africa; dust deposition; Montseny mountains; Quercus ilex L.

Mineralogical composition of African dust delivered by red rains over northeastern Spain - Avila, A.; QueraltMitjans, I.; Alarcon, M. (JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 1997)
The African dust deposition, mineralogy, source regions, and influence on rain chemistry were analyzed for a site in the Montseny mountains (Catalonia, northeastern Spain) for the period August 1, 1983, through August 1, 1994. Dust deposition was highly variable: two events (collected on November 9-11, 1984, and March 22-25, 1991) accounted for 62% of the total dust input in the 38 red rain events recorded in the period. The average annual dust deposition was 5.3 g m(-2) (SE 2.6). Three source regions in the African continent were identified with back trajectory analysis: (1) Western Sahara, (2) Moroccan Atlas, and (3) Central Algeria. Events from the Moroccan Atlas predominated in terms of number of events, amount of rainfall, and dust deposition. The meteorological situations during red rains were identified: Western Sahara events occurred principally with a depression at high latitudes (50 degrees N) forming a trough in the North Atlantic, Moroccan Atlas events occurred with a depression in front of Portugal, and events from central Algeria were associated with a depression over Spain or North Africa. By order of abundance (median of n=13) the minerals identified in the dust by X ray diffraction were as follows: illite > quartz > smectite > palygorskite > kaolinite > calcite > dolomite > feldspars. Differences in mineralogy between source regions were significant for smectite, kaolinite, quartz, and dolomite. Smectite and kaolinite content was highest in the Algerian events, while quartz and dolomite content was lowest. Events from the Moroccan Atlas had the lowest smectite and kaolinite. The red rain soluble chemistry was clearly influenced by the dissolution of calcite (high alkalinity, calcium concentration and basic pH) and by marine components (high Na+, Cl- and Mg+2 concentrations). Because of the very alkaline character of red rains they had a strong weight on the annual mean pH of rainwater. This was reflected by the significant relationship (r=0.71, p<0.01) between the percentage of annual precipitation as red rain and annual mean precipitation pH. Red rains provided 25-45% of the annual dissolved input of the major ions in precipitation and 34% of the calcium required for helm oak (Quercus ilex L.) forest growth at the study site.
APSAPSThe following values have no corresponding Zotero field: pub-location: 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA publisher: AMER GEOPHYSICAL UNION
Keywords: Africa; dust deposition; Montseny mountains; Quercus ilex L.

Modelling the hydrological response of mediterranean catchments, Prades, Catalonia. The use of distributed models as aids to hypothesis formulation - PIÑOL, JOSEP; BEVEN, KEITH; FREER, JAMES (Hydrological Processes, 1997)
This paper attempts to extend the physical arguments underlying the distributed TOPMODEL concepts in an application to the strongly seasonal contributing area responses in two adjacent small mediterranean catchments in the Prades region of Catalonia, Spain. A perceptual model of hydrological response in these catchments is used to suggest possible modifications of the model in a hypothesis testing framework, including an attempt to modify the topographic index approach to reflect the expansion of the effective area of subsurface flow during the wetting-up sequence. It is found that slight improvements in modelling efficiency are possible but that different model parameter distributions are appropriate for different parts of the record. The model was much more successful for the catchment producing the higher runoff volumes. © 1997 John Wiley & Sons, Ltd.
Keywords: Mediterranean hydrology; rainfall–runoff models; TOPMODEL

Modelling transpiration in holm-oak savannah: scaling up from the leaf to the tree scale - Infante, J M; Rambal, S; Joffre, R (Agricultural and Forest Meteorology, 1997)
The transpiration of oak-savannas in southern Spain was modelled by scaling-up from the leaf to the tree during a drought period. Two chlaracteristics of this ecosystem were found to facilitate the modelling procedure. The first was a near-zero decoupling coefficient between the surface and the surrounding bulk air, which simplifies the transpiration formulation. The second was that the surface conductance (g) is mainly related to the vapour pressure deficit of the air (0,). Based on both of these characteristics, the modelling procedure provides a general model of transpiration over the time scale appropriate for a drought period, from days to months. The response of g to 0, was found to follow a negative exponential function, such that beyo’nd a minimum value, g becomes independent of 0,. This implies a feedback control on g by 0,. The consequences of tbis control for transpiration were found at different levels of plant water status. This explains the plants’ adaptation to long dry periods, even though there is also continuous water loss during these periods. Such an adaptation was corroborated by a seasonal hysteresis found in the relationship between transpiration and D, as a function of the plants’ water status
Keywords: oak savannas; seasonal hysteresis; southern Spain; Transpiration; vapour pressure deficit

Morphological adjustments of mature Quercus ilex trees to elevated CO 2 - Hättenschwiler, S; Miglietta, Franco; Raschi, Antonio; Körner, C (Acta Oecologica, 1997)
It is still not known whether mature forest trees respond to increasing atmospheric CO 2 concen- trations in similar ways as seedlings do. Mature Mediterranean oaks (Qaercus ilex) growing in a CO 2 enriched atmosphere around natural CO 2 vents since the seedling stage showed a moderate, age- dependent increase in stem biomass production, but had significantly lower biomass of 6-year-old branches, decreased branching, and lower leaf area per unit branch biomass, compared to control trees at a nearby unenriched site. Our data indicate that trees in natural forest stands morphologically adjust to increasing CO 2 and reduce COz-induced initial growth stimulations. Allometric adjustments such as reduction in leaf area may be regarded as a "down-regulation" of canopy photosynthesis and may be an effective mechanism for saving water.
Keywords: allometric adjustments; biomass allocation; branch morphology; branching; leaf area; Mediterranean; natural co 2 springs; Quercus ilex

Morphological adjustments of mature Quercus ilex trees to elevated CO 2 - Hättenschwiler, S.; Miglietta, Franco; Raschi, Antonio; Körner, C. (Acta Oecologica, 1997)
It is still not known whether mature forest trees respond to increasing atmospheric CO 2 concen- trations in similar ways as seedlings do. Mature Mediterranean oaks (Qaercus ilex) growing in a CO 2 enriched atmosphere around natural CO 2 vents since the seedling stage showed a moderate, age- dependent increase in stem biomass production, but had significantly lower biomass of 6-year-old branches, decreased branching, and lower leaf area per unit branch biomass, compared to control trees at a nearby unenriched site. Our data indicate that trees in natural forest stands morphologically adjust to increasing CO 2 and reduce COz-induced initial growth stimulations. Allometric adjustments such as reduction in leaf area may be regarded as a "down-regulation" of canopy photosynthesis and may be an effective mechanism for saving water.
Keywords: allometric adjustments; biomass allocation; branch morphology; branching; leaf area; Mediterranean; natural co 2 springs; Quercus ilex

Mortalidad y crecimiento de plantones de quercus ilex en una tierra agrícola abandonada en toledo - Rey Benayas, Jose Maria (II Congreso Forestal Español, 1997)
Considerable quantities of agricultural land are being transformed into forested lands in E.U. countries. To assess afforestation practice, we analyzed the growth and mortality of 800 Quercus ilex' subsp. ball()ta seedlings in a set-aside agricultural land under semi-arid Mediterranean climate conditions in Toledo, Spain. The mortality and growth of the seedlings were monitored for three years after planting with an experimental design that included all four combinations of i) irrigation or no irrigation in the dry season and ii) artificial shading or no shading. Significant differences in mortality and growth (height, stem diameter and crown projected area) were found among treatments. Mortality was highest (47%) in the control plots, and very similar (around 7%) for the irrigation, shade, and combined treatments. Most of the mortality occurred after the first dry season. The low mortality in irrigated but not shaded plots in the first dry season is attributed to the protective role of a thick layer of the weed Amaranthus retroflexus L. Seedling growth was greatest on average under irrigation and shade conditions. Shade was found to have a significant effect for all growth measurements, while irrigation alone only affected stem diameter growth, and crown projected area in interaction with shade. We conclude that the reduction of summer stress must be considered in the early stages for successfull afforestation practices with oaks in set-aside agricultural lands of dry environments.
Keywords: Agriculturalland; Growth; irrigation; shade; Survival

Multiplicación vegetativa de alcornoque mediante embriogénesis somática. - Garcia-Martin, G.; Fernandez-Galiano, E.; Mauri, P. V.; Somática, Embriogénesis (II Congreso Forestal Español, 1997)
In order to obtain cork oak clones from selected individuals, somatic embryogenesis was induced in leaves. Somatic embryos can be continuously subcultured with high proliferation rates. This culture system has sorne limiting factors: low percentage of mature embryos obtained, low rate of shoot emergence during germination and high labour and time consumed. Exogenous addition of ABA (l0-6M) concentration during proliferation increased maturation rateo In the same way addition of. BAP (0,001 mg/l) had a positive effect on shoot production. With the aim to obtain a first approach to automation the best culture media for both culture cycles of maturation in liquid medium were determined.
The following values have no corresponding Zotero field: periodical: II Congreso Forestal Español pub-location: Pamplona
Keywords: ABA; BaP; Cork oak; germination; liquid culture; maturation; somatic embryos

Multiplicación vegetativa de alcornoque mediante embriogénesis somática. - GARCÍA-MARTÍN, G; Fernandez-Galiano, E; Mauri, P V; Somática, Embriogénesis (II Congreso Forestal Español, 1997)
In order to obtain cork oak clones from selected individuals, somatic embryogenesis was induced in leaves. Somatic embryos can be continuously subcultured with high proliferation rates. This culture system has sorne limiting factors: low percentage of mature embryos obtained, low rate of shoot emergence during germination and high labour and time consumed. Exogenous addition of ABA (l0-6M) concentration during proliferation increased maturation rateo In the same way addition of. BAP (0,001 mg/l) had a positive effect on shoot production. With the aim to obtain a first approach to automation the best culture media for both culture cycles of maturation in liquid medium were determined.
Keywords: ABA; BaP; Cork oak; germination; liquid culture; maturation; somatic embryos

Mycena quercophila , a new species of Mycena section Polyadelphia growing on Quercus ilex leaves - Vlllarreal, M (Österreichische Zeitschrift für Pilzkunde, 1997)
Mycena quercophila, a member of Mycena section Polyadelphia, is proposed as new. It is characterized by brownish yellow colours of the fruitbodies and smooth to sparsely diverticulate chei- locystidia. Most species of this section show profusely diverticulate cheilocystidia. except the related M terenu. with completely smooth cheilocystidia and with different colours and habitat. A colour figure and microscopical drawings of the new species are added
Keywords: Agaricales; Basidiomvcetes; Mycena quercophila; Mycoflora of Spain; new species; systematics; taxonomy; Trichulomataceue

Nitrogen availability in composted cork - Carmona, E; Ordovas, J; Ortega, M C; Aguado, M T (INTERNATIONAL SYMPOSIUM ON GROWING MEDIA AND PLANT NUTRITION IN HORTICULTURE, 1997)
Previous studies showed that plants grown in fresh cork (Quercus suber L. bark) had a reduced growth compared with peat and low rates of N. In composted cork, however, plant growth was similar with those in peat, but the N content of plants was still slightly lower. The purpose of this study was to investigate N availability in fresh and composted cork during 4, 5.5 and 7 months, using peat as control medium. The substrates were also incubated at 25 degrees C during 60 days after adding 0.25, 1.0, 1.75 or 3.0 g ammonium nitrate per 1 of substrate. Samples were taken periodically to measure NO3-N, NH4-N and total N. Also the Nitrogen Drawdown Index (NDI) for the addition of 75 mg.l(-1) N and 150 mg.l(-1) N was measured after incubation at 25 degrees C. N immobilization rates were well correlated to NDI. NH and soluble N drawed down rapidly in cork substrates while total N stayed constant. High rates of ammonium nitrate should be added to maintain a constant level of available N to plants in cork.
Keywords: Bark; growing media; N immobilization

Nitrogen availability in composted cork - Carmona, E.; Ordovas, J.; Ortega, M. C.; Aguado, M. T. (INTERNATIONAL SYMPOSIUM ON GROWING MEDIA AND PLANT NUTRITION IN HORTICULTURE, 1997)
Previous studies showed that plants grown in fresh cork (Quercus suberL. bark) had a reduced growth compared with peat and low rates of N. In composted cork, however, plant growth was similar with those in peat, but the N content of plants was still slightly lower. The purpose of this study was to investigate N availability in fresh and composted cork during 4, 5.5 and 7 months, using peat as control medium. The substrates were also incubated at 25 degrees C during 60 days after adding 0.25, 1.0, 1.75 or 3.0 g ammonium nitrate per 1 of substrate. Samples were taken periodically to measure NO3-N, NH4-N and total N. Also the Nitrogen Drawdown Index (NDI) for the addition of 75 mg.l(-1) N and 150 mg.l(-1) N was measured after incubation at 25 degrees C. N immobilization rates were well correlated to NDI. NH and soluble N drawed down rapidly in cork substrates while total N stayed constant. High rates of ammonium nitrate should be added to maintain a constant level of available N to plants in cork.
The following values have no corresponding Zotero field: periodical: INTERNATIONAL SYMPOSIUM ON GROWING MEDIA AND PLANT NUTRITION IN HORTICULTURE issue: 450 pub-location: PO BOX 500, 3001 LEUVEN 1, BELGIUM
Keywords: bark; growing media; N immobilization

Organic carbon and nitrogen mineralization under Mediterranean climatic conditions: the effects of incubation depth - Rovira, P.; Vallejo, V. R. (Soil Biology and Biochemistry, 1997)
n a soil profile, temperature and humidity regimes change with depth. Under Mediterra- nean conditions, upper horizons are more affected by water deficits and drying-rewetting cycles than deep horizons. Our aim was to study how carbon and nitrogen mineralization are affected by depth, and special attention is paid to separating the effects of pedoclimate from the effects of other con- straints like amount and quality of organic matter. To this end, mixtures of plant + soil material were exposed by incorporation in the field, at depths of 5, 20 and 40 cm, in nylon mesh bags. Mineralization of C and N was studied for 2 y. For all types of plant material studied (Eucalyptus globulus, Quercus ibex and Pinus halepensis), mineralization of both carbon and nitrogen was lower at 5cm. No differ- ences were between 20 and 40 cm. This result, probably as a result of the higher drying of the upper- most horizons, contrasts with the usual findings on this topic. The amounts of both C and N mineralized were lower than expected, probably because plant materials were finely ground, allowing stabilization in the mineral matrix of soil. With the possible exception of Pinus, depth affected the rate of mineralization, not the relation between C and N. It is concluded that, at least under Mediterranean conditions, the pedoclimate in deep layers is more favourable to microbial activity than in upper layers, in which drought is a strong limiting factor. Reduced oxygen availability in the subsoil layers did not inhibit decomposition and mineralization to the same extent as did desiccation in the surface layer. The higher mineralization of C and N usually found in upper horizons may be attributed to the higher amount and quality of organic matter in these horizons, rather than to pedoclimatic constraints
Keywords: mineralization; organic matter (voyant); Soil depth; water content

Organic carbon and nitrogen mineralization under Mediterranean climatic conditions: the effects of incubation depth - Rovira, P; Vallejo, V R (Soil Biology and Biochemistry, 1997)
n a soil profile, temperature and humidity regimes change with depth. Under Mediterra- nean conditions, upper horizons are more affected by water deficits and drying-rewetting cycles than deep horizons. Our aim was to study how carbon and nitrogen mineralization are affected by depth, and special attention is paid to separating the effects of pedoclimate from the effects of other con- straints like amount and quality of organic matter. To this end, mixtures of plant + soil material were exposed by incorporation in the field, at depths of 5, 20 and 40 cm, in nylon mesh bags. Mineralization of C and N was studied for 2 y. For all types of plant material studied (Eucalyptus globulus, Quercus ibex and Pinus halepensis), mineralization of both carbon and nitrogen was lower at 5cm. No differ- ences were between 20 and 40 cm. This result, probably as a result of the higher drying of the upper- most horizons, contrasts with the usual findings on this topic. The amounts of both C and N mineralized were lower than expected, probably because plant materials were finely ground, allowing stabilization in the mineral matrix of soil. With the possible exception of Pinus, depth affected the rate of mineralization, not the relation between C and N. It is concluded that, at least under Mediterranean conditions, the pedoclimate in deep layers is more favourable to microbial activity than in upper layers, in which drought is a strong limiting factor. Reduced oxygen availability in the subsoil layers did not inhibit decomposition and mineralization to the same extent as did desiccation in the surface layer. The higher mineralization of C and N usually found in upper horizons may be attributed to the higher amount and quality of organic matter in these horizons, rather than to pedoclimatic constraints
Keywords: mineralization; organic matter (voyant); Soil depth; water content

Os principais tipos de utilização do solo no Alentejo meridional: evolução de 1885 e 1951 - Feio, M.; Cordeiro, A. M. (Finisterra: Revista portuguesa de …, 1997)
Partindo das Cartas Agrícolas de G. Pery, do fim do século XIX, e da Carta Agrícola e Florestal do SROA, de meados do século XX, apresenta-se a evolução dos principais tipos de utilização do solo no Alentejo meridional: charneca, culturas arvenses, montado, olivais e vinha. A evolução foi muito grande, principalmente na redução da charneca e no grande aumento das culturas de cereais, causadas pelo proteccionismo do trigo (Elvino de Brito), instituído no fim do séc. XIX, de que resultou considerável aumento de preço deste cereal.
Keywords: agricultura; Alentejo; evolução

Os principais tipos de utilização do solo no Alentejo meridional: evolução de 1885 e 1951 - Feio, M; Cordeiro, A M (Finisterra: Revista portuguesa de …, 1997)
Partindo das Cartas Agrícolas de G. Pery, do fim do século XIX, e da Carta Agrícola e Florestal do SROA, de meados do século XX, apresenta-se a evolução dos principais tipos de utilização do solo no Alentejo meridional: charneca, culturas arvenses, montado, olivais e vinha. A evolução foi muito grande, principalmente na redução da charneca e no grande aumento das culturas de cereais, causadas pelo proteccionismo do trigo (Elvino de Brito), instituído no fim do séc. XIX, de que resultou considerável aumento de preço deste cereal.
Keywords: agricultura; Alentejo; evolução

An overview of the Castelporziano experiments - Seufert, G; Bartzis, J; Bomboi, T; Ciccioli, P; Cieslik, S; Dlugi, R; Foster, P; Hewitt, C N; Kesselmeier, J; Kotzias, D; Lenz, R; Manes, F; et al. (Atmospheric Environment, 1997)
This paper reviews the major outcomes of the measuring campaigns performed at the Castelporziano nature preserve near Rome, Italy, by 14 European laboratories as part of the BEMA (Biogenic Emissions in the Mediterranean Area)-project. Six campaigns of 1–4 weeks duration were carried out in different seasons of the years 1993–1994 at semi-continuously running test plots in the nature reserve, representing common Mediterranean vegetation types. The aim was to characterise, at the different test plots, the atmospheric chemical and meteorological situations, the plant biomass and physiology, the type, amount and controls of emissions from different plants by means of branch enclosures, and the BVOC emission fluxes from different ecosystems, by scaling up enclosure data from individual sources, and by measuring fluxes directly by use of micrometeorological methods. An important focus during the initial phase of the five year BEMA-project was the harmonisation and improvement of the analytical, physiological and micrometeorological methods used, and the development and testing of new methods for measuring BVOC fluxes.
Keywords: air chemistry; Biogenic emission; ecophysiology; Mediterranean area; micrometeorology; Vegetation

PATOGENICIDAD DE HONGOS AISLADOS DEL ALCORNOQUE EN CATALUÑA - LUQUE, J; ÁLVAREZ, I (II Congreso Forestal Español, 1997)
Forty four fungal strains were used in pathogenicity tests made in trunk (32), leaves (8), and roots (8) of cork oak plants (Quereus suber L.) with two irrigation treatments (adequate and stress). Eleven species were found to be pathogenic on tnmk and three on leaf. Trunk pathogens such as Botryosphaeria stevensii, Phytophthora einnamomi, and (?)Diseula sp. caused the death of the inoculated plants. Hydric stress increased both canker and necrosis formation by (?)Diseula sp. and H. mediterraneum, reduced the effects of P. cinnamomi and had no effect on B. stevensii. The latter fungus was a virulent pathogen irrespectively of the irrigation treatment. Dendrophoma myriadea and (?)Fusieoeeum sp. were pathogenic on leaves. Both fungi were negatively affected by the hydric stress. However, no satisfactory results were obtained in the root inoculations. K.W.:
Keywords: Botryosphaeria stevensii; decline; Hypoxylon mediterraneum; pathogenic fungi; phytophthora cinnamomi; Quercus suber

Photochemical reflectance index and leaf photosynthetic radiation-use-efficiency assessment in Mediterranean trees - Penuelas, J; Llusia, J; Piñol, J; Filella, I (International Journal of Remote Sensing, 1997)
Abstract This Letter presents new data validating the use of the photochemical reflectance index PRI (R570-R531)/(R570 + R531) to assess photosynthetic- radiation-use-efficiency under mild water stress. Gas exchange, fluorescence and the PRI of leaves from the Mediterranean trees Quercus ilex and Phillyrea latifolia growing in the field were followed from spring to summer 1996 in central Catalonia (NE Spain). The same variables were measured in seedlings of these two species and Pistacia lentiscus submitted to progressive drying after witholding irrigation. Except for severely drought damaged plants, significant relations of the reflectance index PRI with fluorescence yield of the photosystem II (Delta F/F' m), non photochemical fluorescence quenching ( qN ) and photosynthetic radiation use efficiency (PRUE) were found, thus indicating a functional relation among these parameters. A simple portable radiometer measuring ground level reflectance at narrow bands centred at 531 and 570nm could instantaneously calculate the PRI index and give the PRUE estimation.
doi: 10.1080/014311697217387
Keywords: Fluorescence (voyant); Gas exchange; photochemical reflectance index PRI; photosynthetic radiation use efficiency

Photosynthetic activity of Quercus ilex at the extremes of a transect between Mediterranean and submediterranean vegetation (Trieste NE Italy) - Tretiach, M.; Bolognini, G.; Rondi, A. (FLORA, 1997)
Microclimatic data and CO2 gas exchange rates were measured in thecoastal area near Trieste (NE Italy) in two groups of plants rowing at the extremes of a floristic-vegetational gradient between an evergreen Mediterranean maquis on the coast and a winter deciduous submediterranean woodland on the Karst plateau, where Q. ilex persists only sporadically but is still a co-dominant tree. Field data were recorded from sunrise to sunset during the periods of highest productivity and of maximum physiological stress. i.e. high temperatures and water deficit in summer, and low temperatures and strong, dry winds in winter. Photosynthesis was measured with a portable Infrared Gas Analyzer. Microclimatic data showed that summer and winter stress were more intense on the Karst plateau. Assimilation of the coastal population was higher because a positive CO2 balance was maintained during both stress periods. During summer drought stress diurnal assimilation of the inland population was just in balance with nocturnal leaf respiration. In winter, on the contrary, photosynthetic activity ceased almost completely for almost a week, due to the lower temperature regime and to strong, dry winter winds that caused severe mechanical damages and, more generally, a drastic shortening of the leaf life span. The competition ability of Q. ilex in ecotonal areas is briefly discussed on the basis of these results. Winter stress seems to be the main factor limiting the distribution of Q. ilex northwards.
The following values have no corresponding Zotero field: pub-location: VILLENGANG 2, D-07745 JENA, GERMANY publisher: GUSTAV FISCHER VERLAG
Keywords: competition; CO2; drought stress; gradient; photos

Photosynthetic activity of Quercus ilex at the extremes of a transect between Mediterranean and submediterranean vegetation (Trieste NE Italy) - Tretiach, M; Bolognini, G; Rondi, A (FLORA, 1997)
Microclimatic data and CO2 gas exchange rates were measured in the coastal area near Trieste (NE Italy) in two groups of plants rowing at the extremes of a floristic-vegetational gradient between an evergreen Mediterranean maquis on the coast and a winter deciduous submediterranean woodland on the Karst plateau, where Q. ilex persists only sporadically but is still a co-dominant tree. Field data were recorded from sunrise to sunset during the periods of highest productivity and of maximum physiological stress. i.e. high temperatures and water deficit in summer, and low temperatures and strong, dry winds in winter. Photosynthesis was measured with a portable Infrared Gas Analyzer. Microclimatic data showed that summer and winter stress were more intense on the Karst plateau. Assimilation of the coastal population was higher because a positive CO2 balance was maintained during both stress periods. During summer drought stress diurnal assimilation of the inland population was just in balance with nocturnal leaf respiration. In winter, on the contrary, photosynthetic activity ceased almost completely for almost a week, due to the lower temperature regime and to strong, dry winter winds that caused severe mechanical damages and, more generally, a drastic shortening of the leaf life span. The competition ability of Q. ilex in ecotonal areas is briefly discussed on the basis of these results. Winter stress seems to be the main factor limiting the distribution of Q. ilex northwards.
Keywords: CO2; competition; Drought stress; Gradient; photos

Plan de calas de corcho y establecimiento de rodales selectos de alcornoque en andalucía - Carrasco, Angel; BORRERO, GUMERSINDO; CAMPAYO, P; RODRIGUEZ, M; ÁLVAREZ, J.Ma; FARIÑA, J.Ma; E.TORRES; Privado, Consultor; La, C I; Manojo, D E L; Madrid, D E Rosas (II Congreso Forestal Español, 1997)
Since 1995, the "Consejería de Medio Ambiente" of the "Junta de Andalucía" has been developping a "Cork samples Plan and Establishment of select "Areas" of the Quercus suber". This plan is intended to collect technical-scientifical information, used both for a better knowledge of the cork oak forests and their principal product, cork, as well as for the elaboration of a cork quality map of the Andalusian Community. They also provide cork- tree owners with information about the explotation quality, for which cork samples are taken both from cork trees and from cork-piles. Using the collected samples, once they are classified and analised in the laboratory, and according to the data collected in the field, quality reports on cork are effec~ll(lted for the owner. Subsequently, these samples are show in a permanent exposition in thejaboratorywhere buyers or any other person interested can obtain information about the quality offered in the different Andalusian forests. Since 1995, the obtained information is also being used, amplifying the data taken referent to select "areas" of the cork oak forests to be able to establish a select "areas" network of Quercus suber capable of producing high quality acorns.
Keywords: Andalucía; Cork; cork-oak; Quercus suber; Select "areas"

Plan de calas de corcho y establecimiento de rodales selectos de alcornoque en andalucía - Carrasco, Angel; BORRERO, GUMERSINDO; CAMPAYO, P.; RODRIGUEZ, M.; ÁLVAREZ, J. Ma; FARIÑA, J. Ma; E. TORRES; Privado, Consultor; La, C. I.; Manojo, D. E. L.; Madrid, D. E. Rosas (II Congreso Forestal Español, 1997)
Since 1995, the "Consejería de Medio Ambiente" of the "Junta de Andalucía" has been developping a "Cork samples Plan and Establishment of select "Areas" of the Quercus suber". This plan is intended to collect technical-scientifical information, used both for a better knowledge of the cork oak forests and their principal product, cork, as well as for the elaboration of a cork quality map of the Andalusian Community. They also provide cork- tree owners with information about the explotation quality, for which cork samples are taken both from cork trees and from cork-piles. Using the collected samples, once they are classified and analised in the laboratory, and according to the data collected in the field, quality reports on cork are effec~ll(lted for the owner. Subsequently, these samples are show in a permanent exposition in thejaboratorywhere buyers or any other person interested can obtain information about the quality offered in the different Andalusian forests. Since 1995, the obtained information is also being used, amplifying the data taken referent to select "areas" of the cork oak forests to be able to establish a select "areas" network of Quercus suber capable of producing high quality acorns.
The following values have no corresponding Zotero field: periodical: II Congreso Forestal Español
Keywords: Andalucía; Cork; cork-oak; Quercus suber; Select "areas"

PLANTACIÓN Y SIEMBRA DE Quereus ilex L.: EFECTOS DE LA PREPARACIÓN DEL TERRENO Y DE LA UTILIZACIÓN DE PROTECTORES EN LA SUPERVIVENCIA DE PLANTAS - Ambiente, Ministerio D. E. Medio; NICOLÁS PERAGÓN, J. L.; DOMINGUEZ LERENA, S.; HERRERO SIERRA, N.; VILLAR- SALVADOR, P. (II Congreso Forestal Español, 1997)
In a first experiment the effect of two tillage treatments, a deep mechanical tillage and no tillage, on the survival of seeded Quercus ilex seedlings was analysed. In a second experiment the influence of acorn seeding versus plantation of containerized seedling, as well as the effect of two types of treeshelters (with and without lateral ventilation holes) and treeshelter removal in summer on the survival of Q. ilex seedlings was studied. Microclimate inside treeshelters containing seedlings was also measured along a typical summer day. Deep tillage increased germination and survival in comparison with untilled treatment. Temperature and leaf to air vapor pressure deficit was higher inside the treeshelters, specially in those without wholes, than outside. In spite of this fact, both treeshelter types, and particularIy those with lateral ventilation holes, exhibited a higher survival percentages than the control without treeshelter. Neither acorn seeding nor the removal of treeshelters in summer improved survival. significantly.
The following values have no corresponding Zotero field: periodical: II Congreso Forestal Español pub-location: Pamplona
Keywords: Acorn seeding; Holm oak; microclimate; Reforestation; Tillage

PLANTACIÓN Y SIEMBRA DE Quereus ilex L.: EFECTOS DE LA PREPARACIÓN DEL TERRENO Y DE LA UTILIZACIÓN DE PROTECTORES EN LA SUPERVIVENCIA DE PLANTAS - Ambiente, Ministerio D E Medio; NICOLÁS PERAGÓN, J L; DOMÍNGUEZ LERENA, S; HERRERO SIERRA, N; VILLAR- SALVADOR, P (II Congreso Forestal Español, 1997)
In a first experiment the effect of two tillage treatments, a deep mechanical tillage and no tillage, on the survival of seeded Quercus ilex seedlings was analysed. In a second experiment the influence of acorn seeding versus plantation of containerized seedling, as well as the effect of two types of treeshelters (with and without lateral ventilation holes) and treeshelter removal in summer on the survival of Q. ilex seedlings was studied. Microclimate inside treeshelters containing seedlings was also measured along a typical summer day. Deep tillage increased germination and survival in comparison with untilled treatment. Temperature and leaf to air vapor pressure deficit was higher inside the treeshelters, specially in those without wholes, than outside. In spite of this fact, both treeshelter types, and particularIy those with lateral ventilation holes, exhibited a higher survival percentages than the control without treeshelter. Neither acorn seeding nor the removal of treeshelters in summer improved survival. significantly.
Keywords: Acorn seeding; Holm oak; microclimate; Reforestation; Tillage

PRODUCCIÓN DE PLANTA CLONAL DE QUERcus ILEX L. MEDIANTE EMBRIOGÉNESIS SOMÁTICA PARA MICORRIZACIÓN CON TUBER MELANOSPORUM Vitt. - Mauri, P V; Garcia, G; Fernandez-Galiano, E (II Congreso Forestal Español, 1997)
Quercus ilex L. is the most important tree for the micorritation with Tuber melanosporum Vitt. Quercus ilex L. acorns were collected during the summer and they were surface sterilized with a 15% NaC10H solution. Zygotic embryos were then plated in darlrness during 30 days in a MS medium containing PRL-4-C macrosalts. Different concentrations of growth regulators (NAA, BA and 2,4D) were added to the basic medium for inducting somatic embryogenesis. Explants were transferred to a basal medium supplemented with 0,5 MBA and 0,5 MNAA, during 30 days in light. The somatic embryogenesis response appeared in every media assayed, even in the one with no PGRs, except in those containing 3. M 2,4D. The somatic embryos appeared from embryogenic yellow, friable callus or directly from the apical axis. Once the embryonic callus was transferred to PGRs free medium, secondary embryogenesis appeared repetitively. Somatic embryogenesis in Quercus ilex L. seems not to dependent on the PGRs added, appearing even with no PGRs. Secondary embryogenesis allows a continuing production of somatic embryos, essential to obtain high amounts of clonal plants.
Keywords: Plant Growth Regulators; Quercus ilex L.; secondary embryogenesis; Somatic embryogenesis; Tuber melanosporum Vitt.; zygotic embryos

A quantitative approach to cork oak forest management - Borges, JoséG; Oliveira, Ângelo C.; Costa, Maria a (Forest Ecology and Management, 1997)
Mathematical programming is one quantitative technique that can be used for strategic and tactical natural resources planning. It has been extensively used both at private and public forest planning levels. Nevertheless, most applications concentrate on modelling of systems involving timber harvesting. This paper focuses on cork oak (Quercus suber L.) forest management. It summarizes the methodology to follow in order to generate information needed for modelling purposes. It formulates a cork oak forest management problem using a linear programming model. A case study is used to illustrate the procedure used. The results of the research on a modelling approach to cork oak forest management for an area extending over 5272 ha in the Portuguese submediterranean ecological region are presented. Extensions to this study are identified.
Keywords: Forest regulation; Harvest scheduling; Linear programming; Mediterranean forestry; Quercus suber L.; Strategic planning

Quantitative ethnopharmacological study of the Campidano Valley and Urzulei district, Sardinia, Italy. - Bruni, a; Ballero, M.; Poli, F. (Journal of ethnopharmacology, 1997)
A new method has been developed for quantitative, phytotherapeutical analysis with a goal to create a general tool suitable for a wide range of research situations. This tool would allow one to gather data in such a format as to facilitate comparison with studies from other areas. The method was applied to data gathered from two sites in Sardinia, Italy (Campidano and Urzulei). Analysis was performed on 2635 responses (a) by plant, (b) by plant part, (c) by medicinal preparation and (d) by therapeutic use. This yielded specificity indexes which proved useful in comparing phytotherapeutic applications in the two geographic areas under study. In Urzulei the original phytotherapeutic heritage is deeply rooted in the local socio-economic history and clearly reflects the area's geographic isolation. Indeed, in this area, there is little reliance on modern health care. On the other hand, in Campidano, the body of phytotherapeutic application is more extensive. Indeed, due to migration-and to a lesser extent isolation- the latter area has been more affected by technological interference and cultural overlapping. In this area attention is widely focused on such modern ailments as glycemia, hypertension and constipation.
The following values have no corresponding Zotero field: accession-num: 9254113
Keywords: Medicinal plants; Quantitative ethnopharmacology; Sardinia; Traditional phytotherapy

Quantitative ethnopharmacological study of the Campidano Valley and Urzulei district, Sardinia, Italy. - Bruni, a; Ballero, M; Poli, F (Journal of ethnopharmacology, 1997)
A new method has been developed for quantitative, phytotherapeutical analysis with a goal to create a general tool suitable for a wide range of research situations. This tool would allow one to gather data in such a format as to facilitate comparison with studies from other areas. The method was applied to data gathered from two sites in Sardinia, Italy (Campidano and Urzulei). Analysis was performed on 2635 responses (a) by plant, (b) by plant part, (c) by medicinal preparation and (d) by therapeutic use. This yielded specificity indexes which proved useful in comparing phytotherapeutic applications in the two geographic areas under study. In Urzulei the original phytotherapeutic heritage is deeply rooted in the local socio-economic history and clearly reflects the area's geographic isolation. Indeed, in this area, there is little reliance on modern health care. On the other hand, in Campidano, the body of phytotherapeutic application is more extensive. Indeed, due to migration-and to a lesser extent isolation- the latter area has been more affected by technological interference and cultural overlapping. In this area attention is widely focused on such modern ailments as glycemia, hypertension and constipation.
Keywords: Medicinal plants; Quantitative ethnopharmacology; Sardinia; Traditional phytotherapy

Quercus ilex resprouts after fire: response to photoinhibition. - Aranda, X.; Hogan, K.; Llorens, L.; Fleck, I. (PLANT PHYSIOLOGY, 1997)
The study was located on Serra del Garraf mountains, Barcelona, NE Spain, overlooking the Mediterranian sea at 530 m. On August 1995 a wild fire consumed 100 hectares of the forest. In spring 1996 four plots were set (100 x
APSAPSThe following values have no corresponding Zotero field: pub-location: 15501 MONONA DRIVE, ROCKVILLE, MD 20855 publisher: AMER SOC PLANT PHYSIOLOGISTS
Keywords: Mediterranean; wild fire

Quercus ilex resprouts after fire: response to photoinhibition. - Aranda, X; Hogan, K; Llorens, L; Fleck, I (PLANT PHYSIOLOGY, 1997)
The study was located on Serra del Garraf mountains, Barcelona, NE Spain, overlooking the Mediterranian sea at 530 m. On August 1995 a wild fire consumed 100 hectares of the forest. In spring 1996 four plots were set (100 x
APS
Keywords: Mediterranean; wild fire

Relación entre la densidad de la masa y la producción de corcho en montes alcornocales del sur de españa - Álvarez, E Torres; González, G Montero; Suárez, M A; Cámara, D E L A; Torres Álvarez, E; Montero González, G; Suárez de la Cámara, M A (II Congreso Forestal Español, 1997)
In this paper the influence of cork-oak stand density on quantity and quality cork production is studied. Seventy five experimental plots were installed at Cortes de la Frontera (Málaga, Spain) cork-oak forests. Sorne stand and productive variables for different basal area were studied. The statistical analysis of the data permit to propose 20-25 m2!ha basal area as the optimum stand density
Keywords: cork-oak; Quercus suber; silviculture; stand density

Relación entre la densidad de la masa y la producción de corcho en montes alcornocales del sur de españa - Álvarez, E. Torres; González, G. Montero; Suárez, M. A.; Cámara, D. E. L. A.; TORRES ÁLVAREZ, E.; Montero González, G.; Suárez de la Cámara, M. A. (II Congreso Forestal Español, 1997)
In this paper the influence of cork-oak stand density on quantity and quality cork production is studied. Seventy five experimental plots were installed at Cortes de la Frontera (Málaga, Spain) cork-oak forests. Sorne stand and productive variables for different basal area were studied. The statistical analysis of the data permit to propose 20-25 m2!ha basal area as the optimum stand density
The following values have no corresponding Zotero field: periodical: II Congreso Forestal Español pub-location: Pamplona
Keywords: cork-oak; Quercus suber; silviculture; stand density

RESPOSTAS ECO-FISIOLÓGICAS DAS ÁRVORES AO C02 ELEVADO E AO STRESS AMBIENTAL NAS CONDIOES DE CLIMA MEDITERRÁNICO - Chaves, M M; Pereira, J S (II Congreso Forestal Español, 1997)
Research on the effects of climatic global changes on trees is particularly relevant because forests are the main biotic reservoir for carbon at the global scale. Research in this area and its interaction with the environmental stresses on Mediterranean trees is stilllimited. In terms of growth response to elevated C02 Mediterranean trees may not be different from the Temperate zone trees, i.e., growth enhancement seems to be short-lived with a decline after the first hrowing seasons. In Mediterranean landscapes important soil fertility gradients, namely nitrogen can be found, which can interfere with response to elevated C02, as shown by our results on Fraxinus angustifolia and Quercus suber. On the other hand, in the Mediterranean aninteraction between elevated C02 and other "summer stresses", like water deficits and elevated temperature and light, is likely to occur. We discuss the possibility that elevated C02 may alleviate sorne of the negative effects of these stresses.
Keywords: Alterações globais; CO2 elevado na atmosfera; Fraxinus angustifolia; Quercus ilex; Quercus suber

Resprouting of Quercus suber in NE Spain after fire - Pausas, J G (Journal of Vegetation Science, 1997)
Many Mediterranean species have evolved strategies that allow them to survive periodic wildfires. Quercus suber trees resprout after fire, some from stem buds and others from basal buds only. In the former case the canopy recovers quickly. In the latter case the stem dies but the tree survives and regrows from basal sprouts. The probability of stem death and the degree of height recovery were studied after a fire in a Q. suber forest in NE Spain using logistic regression analysis. The results suggest that most trees survive after fire; the probability of stem death is negatively related to tree diameter; and recovery is positively related to tree diameter and to bark thickness. Implication for management and conservation of cork-oak forests are discussed.
Keywords: Cork oak; disturbance; Mediterranean; sprouting

Restauración del bosque mediterráneo: aplicación de modelos de restauración a los encinares. - DE SIMÓN NAVARRETE, E; Investigaci, Nnavarrete Centro D E; Apartado, Agraria D E Granada (II Congreso Forestal Español, 1997)
The activities in order to restore the mediterraneam forests have been constitued by the restoration of the structures and natural vegetation communities in order to preserve the water and soil in the drainage basins. A restoration of the vegetation covers in a drainage basin with hydrological and biological criteria have been projected, using sorne reforestation works in order to the best utilitation of the water resources and the conservation of the soil. The Quercus rotundifolia is one of the most extended species in the mediterranean area and it is apply for the forestation of the lands. This paper proposes a model of applied for its restoration. K.W.:
Keywords: Evolution; hydrological process; mediterranean forest; Restoration; structure

Restauración del bosque mediterráneo: aplicación de modelos de restauración a los encinares. - DE SIMÓN NAVARRETE, E.; Investigaci, Nnavarrete Centro D. E.; Apartado, Agraria D. E. Granada (II Congreso Forestal Español, 1997)
The activities in order to restore the mediterraneam forests have been constitued by the restoration of the structures and natural vegetation communities in order to preserve the water and soil in the drainage basins. A restoration of the vegetation covers in a drainage basin with hydrological and biological criteria have been projected, using sorne reforestation works in order to the best utilitation of the water resources and the conservation of the soil. The Quercus rotundifolia is one of the most extended species in the mediterranean area and it is apply for the forestation of the lands. This paper proposes a model of applied for its restoration. K.W.:
The following values have no corresponding Zotero field: periodical: II Congreso Forestal Español pub-location: Pamplona
Keywords: Evolution; hydrological process; mediterranean forest; Restoration; structure

Rooting responses of three oak species to low oxygen stress - Jacobs, K A; Berry, A M; MacDonald, J D; Costello, L R (PROCEEDINGS OF A SYMPOSIUM ON OAK WOODLANDS: ECOLOGY, MANAGEMENT, AND URBAN INTERFACE ISSUES, 1997)
Rooting characteristics were compared in blue (Q. douglasii), valley (Q. lobata), and cork oak (Q. suber) seedlings under hypoxic (low oxygen) conditions. A 50 percent reduction in root growth occurred in all species at an oxygen level of 4 percent, or an oxygen diffusion rate of 0.3 mu g cm(-2)min(-1). Blue oak formed few lateral roots regardless of oxygen level, but valley and cork oak root production decreased under hypoxic conditions. Four percent soil oxygen might be viewed as a minimum requirement for sustaining root growth of oaks in the field, and differences in root branching morphology may be correlated with tolerance of root hypoxia.

Scaling up the biogenic emissions from test sites at Castelporziano - Lenz, Roman; Selige, Thomas; Seufert, Günther (Atmospheric Environment, 1997)
On the basis of measurements of emission rates, Leaf Area Indices (LAI) and biometric data for 17 species and 15 land-cover types, a first scaling up of biogenic emissions for the Castelporziano test site is elaborated It includes the application of different procedures for scaling up, by combining parameters (e.g. LAI, biomass, vegetation coverage, canopy layering, insolation) with emission rates and algorithms in a spatial model. This approach consists of the following steps: (i) elaboration of a pseudo-3D Geographical Information System (GIS) for the test site St. Quercio, and 2D GIS for pseudosteppe, dunes and whole Castelporziano, (ii) calculations of relations between diameter at breast height (dbh), biomass and LA1 from literature and our own data, at St. Quercio, (iii) application of an insolation model in the stands for one to two canop:y layers and surfaces in a l/4 square meter resolution, at St. Quercio; (iv) classified incoming light is driving the emissions of monoterpenes from Stone pine and Holm oak at the test site St. Quercio. For temperature we do not scale up and apply any algorithm to date, but we can show some preliminary surface temperature data from remote sensing activities, possibly to be used during further campaigns. Calculations of total emission fluxes are intercompared for the test site St. Quercio according to the different calculation rules, e.g. the relevancy of spatial effects. The differences between the biomass-based fluxes and the LAI-based fluxes are in the range of 5-30%. The application of the GIS model for light interception for the pine canopy, and for’two canopy layers for Holm oak, is shown for the open stands at St. Quercio. The resulting biogenic emissions are in good accordance with the ones calculated only via biomass or LAI, and the lower parts of a crown seem to be negligible in terms of biogenic emissions.
Keywords: Biogenic emissions; geographical information system; GIS; Land Cover; light interception; scaling up; spatial modelling; Vegetation

Screening of 18 Mediterranean plant species for volatile organic compound emissions - Owen, S; Boissard, C; Street, R A; Duckham, S C; Csiky, O; Hewitt, C N (Atmospheric Environment, 1997)
Eighteen tree and shrub species were screened for emissions of isoprene and other volatile organic compounds (VOCs) at three locations at Castelporziano (Italy) using a bag-enclosure sampling method followed by GC analysis. Thirty emitted compounds were identified. Temperature sensitivity of emissions of monoterpenes varied between species. Strong temperature dependencies were found for isoprene emissions. For monoterpene-emitting plant species with greatest ground cover in the dunes and macchia habitats, α-pinene, β-pinene and sabinene appeared to be the most frequently and abundantly emitted compounds. Isoprene was the major emission from the shrub species screened in the forest. Emissions from four dominant plant species were scaled up to estimate total fluxes from the dunes and macchia over a daytime period. Species with greatest biomass but low emission rates made a substantial contribution to total emissions.
Keywords: Arbutus unedo; Biogenic emissions; branch enclosure; Chrysanthemum praecox; cistus incanus; Cistus salvifolius; Cytisus sp.; Dittrichia sp.; Erica arborea; Erica multiflora; Helichrysum stoechas; isoprene; Juniperus oxycedrus; Juniperus phoenicea; Monoterpene; myrtus communis; Phillyrea angustifolia; Pinus pinea; Quercus cerris; Quercus ilex; Rubus fruticosus; Spartium junceum; VOCs

Search for factors maintaining terricolous bryoflora richness in isolated habitats .2. Comparison between the sclerophyllous oak groves of the occidental border of the Massif des Maures (Var, France) and their interfaces with the vineyard (in French). - Hebrard, J P; Loisel, R (CRYPTOGAMIE BRYOLOGIE LICHENOLOGIE, 1997)
Processing (FAC) of 74 bryophytoecological releves from 6 forest structures with Quercus ilex or Quercus suber, isolated within the vineyard near Pierrefeu-du-Var (siliceous substratum), and the outlying contact zones : Prunus spinosa - Rubus or Cistus scrubs (I), bare soils or lawns often rich in ruderal species (i). The confrontation of the bryofloristical and the station data shows that ambient humidity and substratum richness in total nitrogen play an important role in the differenciation of terricolous bryophyte communities. Two forest sets, one humid and rich in nitrogen of organic origin (ubac of Defens du Becasson : surface = 77617 m(2), scrub-layer dense), the other dry and poor in that element (isolates and hedges with a surface less than or equal to 13115 m(2), scrub-layer absent) have been defined whereas a third, very xeric set, groups nearly all releves from the contact zone i, where supply in nitrate fertilizer may be important.
APS
Keywords: bryophyts; forests structure; Quercus ilex; Quercus suber

Seasonal and interannual occupation of a forest archipelago by insectivorous passerines - Tellería, J L; Santos, T (OIKOS, 1997)
The distribution of insectivorous passerines was studied in 31 fragments (0.1 to 350 ha) of a helm oak (Quercus ilex) Mediterranean forest archipelago in central Spain for two consecutive springs and winters (1988 to 1990). The study aimed to assess the role of forest size, abundance and other biological traits (nesting site and foraging substrata) of the species in their ability to occupy the fragments. The number of fragments occupied by the species (f(i)) was correlated to their abundance (d(i)) in spring and winter. Spring-to-winter changes of di correlated positively to changes off, due to the incidence of summer migrants but failed to show any significant pattern when restricted to species occurring in both seasons. The between-winter variations of cl, correlated positively with changes in f, while the between-spring changes of both parameters did not correlate, probably because of stronger effects of site fidelity on bird distribution in this period. Between-year persistence in the occupation of fragments was directly related to bird species abundance and, for a given abundance, persistence decreased in the smallest fragments. Hole-nesting species during the 1988 spring and the exploiters of scarce trees or foraging substrata during both winters showed an apparent restriction to colonize the smaller fragments due in parr to changes in habitat structure related to fragmentation. These results support the hypothesis that abundance is a good predictor of the ability of species to occupy and persist in fragments. However, abundance alone does not fully explain the processes that determine these occupancy patterns, since other traits related to the spatial scale of analysis and the suitability of fragments for each bird species are also involved.
APS
Keywords: abundance; biological traits; bird distribution; forest size; Holm oak; insectivorous passerines; mediterranean forest; Quercus ilex

Seasonal changes in xanthophyll composition and photosynthesis of cork oak (Quercus suber L.) leaves under mediterranean climate - García-Plazaola, J. I.; FARIA, T.; Abadía, J.; Chaves, M. M.; Pereira, J. S. (Journal of Experimental Botany, 1997)
Seasonal changes in pigment composition of sun and shade leaves of cork oak (Quercus suber) were studied under field conditions in Portugal. Expanding leaves showed a high concentration of xanthophyll cycle components, violaxanthin, antheraxanthin and zeaxanthin. The pool of violaxanthin plus antheraxanthin plus zeaxanthin (V+A+Z) varied greatly between the seasons, being higher at the end of summer and in winter when photosynthesis was limited by water stress and cold, respectively. The size of V+A+Z pool was associated to synthesis of zeaxanthin in response to an excess of light. In sun leaves, midday A+Z relative content was positively correlated with the V+A+Z pool, whereas in shade leaves A+Z decreased with leaf ageing. In both leaf types A+Z was positively correlated with the non-photochemical quenching (NPQ) of chlorophyll a fluorescence. However, in winter NPQ did not change significantly throughout the day, whereas the (A+Z)/(V+A+Z) increased following the typical daily trend observed in other seasons.
10.1093/jxb/48.9.166710.1093/jxb/48.9.1667
Keywords: chlorophyll fluorescence; pigments; Quercus suber; thermal dissipation; xanthophylls

Seasonal changes in xanthophyll composition and photosynthesis of cork oak (Quercus suber L.) leaves under mediterranean climate - Garcia-Plazaola, J I; Faria, T; Abadia, J; Chaves, M M; Pereira, J S (Journal of Experimental Botany, 1997)
Seasonal changes in pigment composition of sun and shade leaves of cork oak (Quercus suber) were studied under field conditions in Portugal. Expanding leaves showed a high concentration of xanthophyll cycle components, violaxanthin, antheraxanthin and zeaxanthin. The pool of violaxanthin plus antheraxanthin plus zeaxanthin (V+A+Z) varied greatly between the seasons, being higher at the end of summer and in winter when photosynthesis was limited by water stress and cold, respectively. The size of V+A+Z pool was associated to synthesis of zeaxanthin in response to an excess of light. In sun leaves, midday A+Z relative content was positively correlated with the V+A+Z pool, whereas in shade leaves A+Z decreased with leaf ageing. In both leaf types A+Z was positively correlated with the non-photochemical quenching (NPQ) of chlorophyll a fluorescence. However, in winter NPQ did not change significantly throughout the day, whereas the (A+Z)/(V+A+Z) increased following the typical daily trend observed in other seasons.
10.1093/jxb/48.9.1667
Keywords: chlorophyll fluorescence; pigments; Quercus suber; thermal dissipation; xanthophylls

Seed Proteins from Quercus suber - Fonseca, Paula A.; Ferreira, Ricardo B.; Teixeira, Artur R. (Journal of Agricultural and Food Chemistry, 1997)
A study on the extraction and characterization of the cotyledonary proteins from cork oak (Quercus suber L.) seeds is reported. The seed proteins, which constitute approximately 5% of the seed weight, are glutelins on the basis of solubility criteria. They are readily solubilized in sodium borate buffer, pH 10, 50 mM, containing 1% (v/v) ?-mercaptoethanol and 1% (w/v) sodium dodecyl sulfate. This fraction is made up of a large number of polypeptides with molecular masses ranging from 10 to above 100 kDa and occurs in the form of large aggregates. The level of glycosylation is low, with two main glycopolypeptides present (43 and 65 kDa). However, the major polypeptides are not glycosylated. In vitro digestibility studies indicated that trypsin and α-chymotrypsin produce a partial proteolysis of the cotyledonary proteins, particularly among the larger molecular mass polypeptides. The partial proteolysis seen in trypsin digests is not due to the presence of enzyme inhibitors in the seeds. On the other hand, pepsin almost completely digests the seed proteins. Taken together, these results may be considered as a good indication of the potential nutritional quality of the proteins from Q. suber seeds. Keywords: Cork oak; glutelin; in vitro proteolysis; protein; Quercus suber; seed
doi: 10.1021/jf9609486doi: 10.1021/jf9609486The following values have no corresponding Zotero field: publisher: American Chemical Society
Keywords: Cork oak; glutelin; in vitro proteolysis; protein; Quercus suber; seed

Seed Proteins from Quercus suber - Fonseca, Paula A; Ferreira, Ricardo B; Teixeira, Artur R (Journal of Agricultural and Food Chemistry, 1997)
A study on the extraction and characterization of the cotyledonary proteins from cork oak (Quercus suber L.) seeds is reported. The seed proteins, which constitute approximately 5% of the seed weight, are glutelins on the basis of solubility criteria. They are readily solubilized in sodium borate buffer, pH 10, 50 mM, containing 1% (v/v) ?-mercaptoethanol and 1% (w/v) sodium dodecyl sulfate. This fraction is made up of a large number of polypeptides with molecular masses ranging from 10 to above 100 kDa and occurs in the form of large aggregates. The level of glycosylation is low, with two main glycopolypeptides present (43 and 65 kDa). However, the major polypeptides are not glycosylated. In vitro digestibility studies indicated that trypsin and α-chymotrypsin produce a partial proteolysis of the cotyledonary proteins, particularly among the larger molecular mass polypeptides. The partial proteolysis seen in trypsin digests is not due to the presence of enzyme inhibitors in the seeds. On the other hand, pepsin almost completely digests the seed proteins. Taken together, these results may be considered as a good indication of the potential nutritional quality of the proteins from Q. suber seeds. Keywords: Cork oak; glutelin; in vitro proteolysis; protein; Quercus suber; seed
doi: 10.1021/jf9609486
Keywords: Cork oak; glutelin; in vitro proteolysis; protein; Quercus suber; seed

Seguimiento de la regeneración natural de alcornoque bajo condiciones microecológicas diferentes. - Torres Álvarez, E; Montero González, G; de la cámara, m. a. (II Congreso Forestal Español, 1997)
This paper studies the natural regeneration of cork-oak in the forests of Aljibe mountains (Málaga, Spain). A plot for monitoring the development of cork-oak seedlings was installed at Cortes de la Frontera cork-oak forests, under different microecological conditions. To get a plentiful and healthy stock of seedlings is necessary enclose the area and to have a light crown cover, is the main conclusion.
Keywords: cork-oak; natural regeneration; Quercus suber; Sylviculture

SEGUIMIENTO MEDIANTE IMAGENES LANDSAT -TM DE LOS DAÑOS PRODUCIDOS POR UN PERIODO PROLONGADO DE SEQUÍA SOBRE ENCINARES EN SIERRA MORENA ( CÓRDOBA ): PRIMEROS RESULTADOS - NAVARRO, R M; FERNÁNDEZ, P; CHANFREUT, M R; GONZÁLEZ, M P (II Congreso Forestal Español, 1997)
NDVI (Normalized Difference Vegetation Index) images generated from LANDSAT- TM data were recently used to monitor large scale drought patterns and their climatic impact on vegetation. The purpose of this study is to use of the NDVI and SA VI to assess regional drought impacts. A temporal data for the period of July 1991 to September 1995 were used to produce NDVI and SA VI images of region in north Córdoba. Drought areas were delineated with certain threshold values of those indexes. Drought patterns delinated by the NDVI and SA VI reflected anomalies because of vegetation cover. It is suggested that NDVI may be used to construct a large scale drouhgt control model, but a further research should be carry out to analyze temporal and spatial evolution of regional drought.
Keywords: Draught; Quercus; Remote sensing

Selectivity and efficacy of some herbicides in forest plant nurseries. - Del Busto, A; Bimbo, B; Garcia-Espana, V; De Barreda, D G (CONGRESS 1997 - SOCIEDAD ESPANOLA DE MALHERBOLOGIA, PROCEEDINGS, 1997)
A experiment was conducted in a 4 especies of forest plants nurseries Quercus ilex L. Pinus halepensis Mill, Pinus pinea L. and Pistacia terebinthus L. with the following residual herbicides simazine, isoxaben, and thiazopyr. The treatment was done in preemergence of the weeds and the crops. Simazine, isoxaben and the mixture of both herbicides were selective in the four forest plants but thiazopir was phytotoxic.
Keywords: Herbicides; Pinus halepensis Mill; Pinus pinea L.; Pistacia terebinthus L.; plant nurseries; Quercus ilex L.; weeds control

Selectivity and efficacy of some herbicides in forest plant nurseries. - Del Busto, A.; Bimbo, B.; Garcia-Espana, V.; De Barreda, D. G. (CONGRESS 1997 - SOCIEDAD ESPANOLA DE MALHERBOLOGIA, PROCEEDINGS, 1997)
A experiment was conducted in a 4 especies of forest plants nurseries Quercus ilex L. Pinus halepensis Mill, Pinus pinea L. and Pistacia terebinthus L. with the following residual herbicides simazine, isoxaben, and thiazopyr. The treatment was done in preemergence of the weeds and the crops. Simazine, isoxaben and the mixture of both herbicides were selective in the four forest plants but thiazopir was phytotoxic.
The following values have no corresponding Zotero field: periodical: CONGRESS 1997 - SOCIEDAD ESPANOLA DE MALHERBOLOGIA, PROCEEDINGS pub-location: DEPARTAMENTO HORTOFRUTICULTURA , BOTANICA I JARDINERIA ETSEA, UNIVERSITAT LLEIDA, 25198 LLEIDA, SPAIN
Keywords: Herbicides; Pinus halepensis Mill; Pinus pinea L.; Pistacia terebinthus L.; plant nurseries; Quercus ilex L.; weeds control

Self- and cross-pollination effects on pollen tube growth and seed set in holm oak Quercus ilex L (Fagaceae) - Yacine, A; Bouras, F (Ann. For. Sci., 1997)
Patterns of the self-incompatibility system have been more often described for hermaphroditic, entomophilous and short-lived plant species. Quercus ilex is a long-lived, monoecious, anemophilous and highly self-incompatible species. We used pollination experiments to investigate phenotypic responses of the self-incompatibility system. Flowers from 14 individuals of the same stand were hand-pollinated with self-pollen, cross-pollen from a single donor and a mixture of the two types. We observed a slower pollen tube growth and no or nearly no seed production after self-pollination. The more self-pollen tubes reach the style, the more flowers will stop their ovule development, resulting in a high flower abortion rate. In open pollination, pollen load is not a limiting factor, but incompatible pollen may reach stigma simultaneously or before compatible cross-pollen, which will induce an early abortion of flowers. When pollination is qualitatively and quantitatively effective, the regulation of seed production related to the resources availability acts by the late abortion of fruit.
Keywords: pollen tube growth; Quercus ilex L; seed set; self-incompatibility

Self- and cross-pollination effects on pollen tube growth and seed set in holm oak Quercus ilex L (Fagaceae) - Yacine, A.; Bouras, F. (Ann. For. Sci., 1997)
Patterns of the self-incompatibility system have been more often described for hermaphroditic, entomophilous and short-lived plant species. Quercus ilex is a long-lived, monoecious, anemophilous and highly self-incompatible species. We used pollination experiments to investigate phenotypic responses of the self-incompatibility system. Flowers from 14 individuals of the same stand were hand-pollinated with self-pollen, cross-pollen from a single donor and a mixture of the two types. We observed a slower pollen tube growth and no or nearly no seed production after self-pollination. The more self-pollen tubes reach the style, the more flowers will stop their ovule development, resulting in a high flower abortion rate. In open pollination, pollen load is not a limiting factor, but incompatible pollen may reach stigma simultaneously or before compatible cross-pollen, which will induce an early abortion of flowers. When pollination is qualitatively and quantitatively effective, the regulation of seed production related to the resources availability acts by the late abortion of fruit.
Keywords: pollen tube growth; Quercus ilex L; seed set; self-incompatibility

Sintomas de estres hidrico y DE "SECA" EN ENCINAS (Quercus ilex subsp. ballota) INOCULADAS CON Phytophthora cinnamomi EN UNA DEHESA DEL CENTRO DE ESPAÑA - TUSET, JUAN J; HINAREJOS, C; MIRA, J L; COBOS, J M (II Congreso Forestal Español, 1997)
Phytophthora cinnamomi is a causal agent for the "seca" (oak decline) of the Mediterranean Quercus. The disease symptoms consist basically of a decay of the trees canopy that may occur as a slow decline: gradualleaves fall and presence of partially or totally defoliated branches, or as a quick decline: rapid decline of branches, leaves remaining attached sorne time, and dead trees. There may also be blackish gummose exudates on trunk and main branches. The "seca" reached epidemic rates in the various evergreen oaks or cork oaks distributed on Andalusia, Castilla-La Mancha and Extremadura since 1990-91. From then in the soils of these forestry areas and on feeder roots of cork oaks and evergreen oaks, P. cinnamomi were isolated along the climatological seasons until now. The continued presence of the fungi has lead to determine the susceptibility of Q. ilex subsp. hallota on adult trees in the field. Adult evergreen oak plants were inoculated with young mycelium of P. cinnamomi at La Iglesuela (Toledo) in spring, 1994. At two years, the development of this fungus on roots, trunks and branches of evergreen oak:, shows a great pathogenic capacity and it has achieved the reproduction of clear symptoms of "seca"
Keywords: canker; oak: decline; Pathogenicity; phytophthora cinnamomi; Quercus ¡lex subsp. ballota

Stem xylem features in three Quercus (Fagaceae) species along a climatic gradient in NE Spain - VILLAR-SALVADOR, P (Trees-Structure and …, 1997)
Stem xylem features in two evergreen Quercus species (Q. coccifera and Q. ilex) and a deciduous one (Q. faginea) were analysed along an Atlantic-Mediterranean climatic gradient in which rainfall and winter cold experi- ence strong variation. Mean maximum vessel diameter, vessel density, vessel element length, xylem transverse sectional area, Huber value (xylem transverse sectional area per leaf area unit), theoretical leaf specific conductiv- ity (estimated hydraulic conductance per leaf area unit) and total leaf area were determined in 3-year-old branches. Q. faginea presented the widest vessels and the highest theo- retical leaf specific conductivity while Q. coccifera showed the lowest total leaf area and the highest Huber value. Studied features did not exhibit significant correlations with mean minimum January temperature in any species but did show significant relationships with rainfall. In Q. coccifera, mean maximum vessel diameter, vessel element length and theoretical leaf specific conductivity increased with higher rainfall while vessel density decreased. Mean maximum vessel diameter and total leaf area in Q. ilex increased with precipitation whereas variables of Q. faginea did not show any significant trend. Results suggest that aridity, rather than minimum winter temperature, controls stem xylem responses in the studied evergreen species. Q. faginea traits did not show any response to precipitation, probably because this species develops deep roots, which in turn makes edaphic and topographic factors more important in the control of soil water availability. In response to aridity Q. coccifera only exhibits adjustment at a xylem level by reducing its water transport capacity through a reduction of vessel diameter without changing the amount of xylem tissue or foliage, whereas Q. ilex adjusts its water transport capacity in parallel to the foliage area.
Keywords: huber value; Mediterranean climate; rainfall gradient; winter temperature; wood anatomy

Stress-induced formation of haploid plants through anther culture in cork oak (Quercus suber) - Bueno, Maria Angeles; Gomez, Arancha; Boscaiu, Monica; Manzanera, Jose Antonio; Vicente, Oscar (Physiologia Plantarum, 1997)
Induetion of haploid embryos and regeneration of plantlets have been obtained, for the first time, in cork oak (Quercus suber L.) by combining a starvation treatment in anther culture with a mild heat shock at 33°C for 5 days, followed by eulture at 25°C in a simple agar medium without growth regulators. The same conditions had been shown previously to be optimal for embryogenic induction in isolated microspore cultures of' several model species such as tobacco and wheat. These results support the notion that stress, particularly sucrose starvation, a heat shock or a combination of both treatments could be the major and general signal responsible for the inhibition of normal gametophytie development of the mierospores and for the induetion of the alternative embryogenic pathway. A similar approach may be used for the production of haploid and doubled haploids for plant breeding in other species that, like most forest trees, are still recalcitrant in anther culture.
Keywords: anther culture; Cork oak; flow cytometry; Haploid plants; heat shock; Quercus suber; starvation; Stress

Stress-induced formation of haploid plants through anther culture in cork oak (Quercus suber) - Bueno, Maria Angeles; Gomez, Arancha; Boscaiu, Monica; Manzanera, Jose Antonio; Vicente, Oscar (Physiologia Plantarum, 1997)
Induetion of haploid embryos and regeneration of plantlets have been obtained, for the first time, in cork oak (Quercus suber L.) by combining a starvation treatment in anther culture with a mild heat shock at 33°C for 5 days, followed by eulture at 25°C in a simple agar medium without growth regulators. The same conditions had been shown previously to be optimal for embryogenic induction in isolated microspore cultures of' several model species such as tobacco and wheat. These results support the notion that stress, particularly sucrose starvation, a heat shock or a combination of both treatments could be the major and general signal responsible for the inhibition of normal gametophytie development of the mierospores and for the induetion of the alternative embryogenic pathway. A similar approach may be used for the production of haploid and doubled haploids for plant breeding in other species that, like most forest trees, are still recalcitrant in anther culture.
Keywords: anther culture; Cork oak; flow cytometry; Haploid plants; heat shock; Quercus suber; starvation; Stress

Study of a soil Julidae community in Mediterranean forest (Diplopoda, Julida) - Serra, A; Miquel, C; Mateos, E; Vicente, C (ENTOMOLOGICA SCANDINAVICA, 1997)
This work is part of a larger study on the communities of epigean and edaphic arthropods from the Pare Natural de Sant Llorenc de Munt (Barcelona, Spain). The study was performed in an experimental plot in a sclerophyllous forest of Mediterranean climate, consisting mainly of Quercus ilex and Pinus halepensis. Field sampling was performed during 25 consecutive months in order to quantify the density of Julidae. In the experimental plot (40 x 40 m), three horizons were sampled: L+F (leaf litter fall), H (humus), and A (the first five cm oft he mineral layer). Among the studied material, we found four species of Julidae: Cylindroiulus punctatus (Leach, 1815), Cylindroiulus sanctimichaelis Attems, 1927, Leptoiulus belgicus (Latzel, 1884), and Ommatoiulus sabulosus (Linnaeus, 1758), with mean densities of 39.45, 35.22, 3.79 and 0.77 ind./m(2), respectively. We didn't find significant differences in mean density between months during the study period for any of these four species. The vertical distribution along the edaphic profile was evaluated using the index of Usher. All species showed a preference for horizon H, with occasional migrations towards the deeper level A, or the shallower level L/F. The analysis of the distribution of juvenile and adult specimens indicated that the reproductive periods occurred mostly in late winter or spring, while the recruitment occurred in spring-early summer.
Keywords: commun; diplopoda; mediterranean forest; millipede

Suberin composition of reproduction cork from Quercus suber - García Vallejo, M C; Conde, E; Cadahía, E; DeSimon, B F (HOLZFORSCHUNG, 1997)
The monomeric composition of suberins from Spanish Quercus suber was determined by gas chromatography/mass spectrometry in the product of depolymerization of free extractives cork with sodium methoxide-methanol. 1-Alkanols (C-20-C-26)(1.8-6.4%), alkanoic acids (C-20-C-24)(2.2-8.1%), alpha,omega-alkanedioic acids (C-16-C-24)(6.1-10.2%) and omega-hydroxy-alkanoic acids (C-20-C-26, being C-22 and C-24 the most abundant)(28.7-37.3%) are identified. The erythro- and threo-9,10-dihydroxyoctadecanedioic (5.4-7.5%), erythro- and threo-9,10,18-trihydroxyoctadecanoic (7.6-11.8%), 9,10-epoxy-18-hydroxyoctadecanoic (1.2-3.1%) and 9,10-epoxy-octadecanodioic acids (1.0-4.4%) and the unsaturated 18-hydroxy-9-octadecenoic (8.1-11.5%) and 9-octadecenedioic (1.5-2.4%) acids are also important components. Ferulic acid (5.3-9.1%) is the main phenolic component of suberin. The studied samples differ in the relative proportion of the different monomers.
Keywords: Cork; epoxy acids; fatty alcohols; fatty and hydrixy-fatty acids; gas chromatography; gas chromatography/mass spectrometry; phenolics; Quercus suber; suberin

Suberina: o polímero responsá vel pelas propriedades da cortiça - Graça, José; Pereira, Helena (II Congreso Forestal Español, 1997)
The macromolecular structure of suberin, the biopolymer mainly responsable for cork properties, is dicussed. The link of the suberinic aliphatic acids to glycerol is presented, supporting the hypothesis that suberin is a glyceridic polyester. The linkage of this aliphatic part, through ferulic acid, to the aromatic part, and the similarities of the later to lignin, are discussed. K.W.:
Keywords: Cork; ferulic acid; Glycerol; suberin

Supervivencia y crecimiento de encina ALCORNOQUE (Quercus suber) UTILIZANDO SEIS TIPOS DE TUBOS INVERNADERO - NAVARRO CERRILLO, R M; MARTÍNEZ SUÁREZ, A (II Congreso Forestal Español, 1997)
Achieving acceptable survival and growth of oak species on afforestation practices has been difficult. Several alternatives to improve establishment have been proposed, seeing that treesshelters are one of the most effective protection in improving survival and initial growth. Six kinds of treeshelters to improve establisment of Quercus ilex and Quercus suber were investigated
Keywords: Afforestation; Q.suber; Quercus ilex; Treeshelters

Supervivencia y crecimiento de plántulas de encina en función de la intensidad de luz y la disponibilidad de agua - J.Ma, ESPELTA; RETANA, J; Riba, M (II Congreso Forestal Español, 1997)
The response of holm oak seedlings under a gradient of light and water av ail abilit y is analyzed. Seedling survival under all water levels decreased with increasing light. Conceming seedling morphology, both light and water availability changed biomass allocation to roots, stems and leaves, being light the most important source of variation
Keywords: Holm oak; light; Regeneration; Seedling; water

Supervivencia y crecimiento en vivero de planta de calidad micorrizada - Muncharaz, Javier Zazo; Moraga, Juana Royo; BARREAL, RODRÍGUEZ; SÁIZ DE OMEÑACA, JOSÉ A; ZAZO MUNCHARAZ, JAVIER; PEÑUELAS RUBIRA, JUAN L; ROYO MORAGA, JUANA; DOMINGUEZ MuÑoz, JOSÉ A (II Congreso Forestal Español, 1997)
There have been studied the quality in plants of the Quercus generus grow in container through different variable analisys including the miccorhization degree. It is wished to improve the relationships between quality and price of the plants.
Keywords: Cantharellus cibarius; mycorrhizae Tuber melanosporum; Quercus faginea; Quercus ilex; Quercus suber

The terpenoid emission pattern of Quercus coccifera L coincides with the emission pattern found with Quercus ilex L - Hansen, U; Seufert, G (PROCEEDINGS OF EUROTRAC SYMPOSIUM `96 - TRANSPORT AND TRANSFORMATION OF POLLUTANTS IN THE TROPOSPHERE, VOL 2: EMISSIONS, DEPOSITION, LABORATORY WORK AND INSTRUMENTATION, 1997)
Monoterpene and isoprene emission rates from Kermes or Holly oak (Quercus coccifera L.), an evergreen shrub or small tree which is widely present in the Mediterranean area, were investigated in a greenhouse using a dynamic enclosure technique, Monoterpenes emitted with the highest rates from Quercus coccifera were alpha-pinene, sabinene and beta-pinene. alpha-pinene contributed 41 % to the total monoterpene emission, sabinene 28 % and beta-pinene 25 %. The isoprene emission rate was 0.7 % of the total monoterpene emission rate. Standardisation to 30 degrees C revealed a total monoterpene emission rate of 18.7 mu g gLDW(-1) h(-1). The data show that terpenoid emissions from Kermes oak (Quercus coccifera L.) are qualitatively and quantitatively similar to those of Helm oak (Quercus ilex L.). Both species have to be considered as strong monoterpene emitters, Emissions are considerably higher compared to the emission factor of 1.2 mu g C gLDW(-1) h(-1) which was assumed to represent the monoterpene emission rate from Mediterranean ecosystems at standard conditions in a study about a global model of natural VOC emissions.
Keywords: alpha-pinene; beta-pinene; isoterpene; Mediterranean area; Monoterpene; Quercus coccifera L.; sabinene; terpenoid; VOC emissions

The terpenoid emission pattern of Quercus coccifera L coincides with the emission pattern found with Quercus ilex L - Hansen, U.; Seufert, G. (PROCEEDINGS OF EUROTRAC SYMPOSIUM `96 - TRANSPORT AND TRANSFORMATION OF POLLUTANTS IN THE TROPOSPHERE, VOL 2: EMISSIONS, DEPOSITION, LABORATORY WORK AND INSTRUMENTATION, 1997)
Monoterpene and isoprene emission rates from Kermes or Holly oak (Quercus coccifera L.), an evergreen shrub or small tree which is widely present in the Mediterranean area, were investigated in a greenhouse using a dynamic enclosure technique, Monoterpenes emitted with the highest rates from Quercus coccifera were alpha-pinene, sabinene and beta-pinene. alpha-pinene contributed 41 % to the total monoterpene emission, sabinene 28 % and beta-pinene 25 %. The isoprene emission rate was 0.7 % of the total monoterpene emission rate. Standardisation to 30 degrees C revealed a total monoterpene emission rate of 18.7 mu g gLDW(-1) h(-1). The data show that terpenoid emissions from Kermes oak (Quercus coccifera L.) are qualitatively and quantitatively similar to those of Helm oak (Quercus ilex L.). Both species have to be considered as strong monoterpene emitters, Emissions are considerably higher compared to the emission factor of 1.2 mu g C gLDW(-1) h(-1) which was assumed to represent the monoterpene emission rate from Mediterranean ecosystems at standard conditions in a study about a global model of natural VOC emissions.
The following values have no corresponding Zotero field: periodical: PROCEEDINGS OF EUROTRAC SYMPOSIUM `96 - TRANSPORT AND TRANSFORMATION OF POLLUTANTS IN THE TROPOSPHERE, VOL 2: EMISSIONS, DEPOSITION, LABORATORY WORK AND INSTRUMENTATION pub-location: ASHURST LODGE, SOUTHAMPTON, HANTS, ENGLAND S04 2AA
Keywords: alpha-pinene; beta-pinene; isoterpene; Mediterranean area; Monoterpene; Quercus coccifera L.; sabinene; terpenoid; VOC emissions

Testing somaclonal variation using RAPDs in Quercus suber L. somatic embryos. - Gallego, F. J.; Martinez, I. (International Journal of Plant Sciences, 1997)
Focuses on the use of Random Amplified Polymorphic Deoxyribose nucleic acid (RAPD) profiles to test somaclonal variation in Quercus suber L. somatic embryous during recurrent embryogenesis. Number of primers used to amplify DNA from isolated embryos; Use of somatic embryogenesis from immature zygotic embryos; How somaclonal variation was detected.
Keywords: Cork oak; SOMATIC embryogenesis (citation)

Testing somaclonal variation using RAPDs in Quercus suber L. somatic embryos. - Gallego, F J; Martinez, I (International Journal of Plant Sciences, 1997)
Focuses on the use of Random Amplified Polymorphic Deoxyribose nucleic acid (RAPD) profiles to test somaclonal variation in Quercus suber L. somatic embryous during recurrent embryogenesis. Number of primers used to amplify DNA from isolated embryos; Use of somatic embryogenesis from immature zygotic embryos; How somaclonal variation was detected.
Keywords: Cork oak; SOMATIC embryogenesis (citation)

Thirty years of in situ tree growth under elevated CO2: a model for future forest responses? - Hättenschwiler, S; Miglietta, F; Raschi, A; Körner, C (GLOBAL CHANGE BIOLOGY, 1997)
Rising concentrations of atmospheric carbon dioxide have been predicted to stimulate the growth of forest trees. However, long-term effects on trees growing to maturity and to canopy closure while exposed to elevated CO2 have never been examined. We compared tree ring chronologies of Mediterranean Quercus ilex which have been continuously exposed to elevated CO2 (around 650 mu mol mol(-1)) since they were seedlings, near two separate natural CO2 springs with those from trees at nearby ambient-CO2 `control' sites. Trees grown under high CO2 for 30 years (1964-93) showed a 12% greater final radial stem width than those growing at the ambient-CO2 control sites. However, this stimulation was largely due to responses when trees were young. By the time trees were 25-30 y old the annual difference in tree ring width between low and high CO2 grown trees had disappeared. At any given tree age, elevated CO2 had a relatively greater positive effect on tree ring width in years with a dry spring compared to years with more rainfall between April and May. This indicates a beneficial effect of elevated CO2 on tree water relations under drought stress. Our data suggest that the early regeneration phase of forest stands can be accelerated in CO2-enriched atmospheres and that maximum biomass per land area may be reached sooner than under lower CO2 concentrations. In our study, high CO2 grown Q. ilex trees reached the same stem basal area at the age of 26 y as control trees at 29 y,i.e. three years earlier (faster turnover of carbon?). Reliable predictions of the future development of forests need to account for the variable responses of trees over their entire lifetime. Such responses to elevated CO2 can presently only be assessed at such unique field sites.
Keywords: Basal area; Dendrochronology; forest regeneration; Mediterranean forests; natural CO2 springs; Quercus ilex; Tree ring; water relations

Tolerance of Quercus sp. young trees to residual herbicides. - Jimenez, M J; Saavedra, M M (CONGRESS 1997 - SOCIEDAD ESPANOLA DE MALHERBOLOGIA, PROCEEDINGS, 1997)
Residual herbicides were applied over Quercus rotundifolia Lam. (oak) and e. suber L. (cork-tree), before and active growing of trees by spraying and irrigation. Diuron and norflurazone were very phytotoxic. Orizalin and oxyfluorfen were tolerated satisfactorily. The other herbicides (simazine, thiazopyr, linuron + pendimethalin, isoxaben, tribenuron and glyphosate + diflufenican) showed variable responses. The tolerance of the trees was better before shooting than after active growing.
Keywords: diuron; norflurazone; Quercus ilex; Quercus suber; residual herbicides

Tolerance of Quercus sp. young trees to residual herbicides. - Jimenez, M. J.; Saavedra, M. M. (CONGRESS 1997 - SOCIEDAD ESPANOLA DE MALHERBOLOGIA, PROCEEDINGS, 1997)
Residual herbicides were applied over Quercus rotundifolia Lam. (oak) and e. suber L. (cork-tree), before and active growing of trees by spraying and irrigation. Diuron and norflurazone were very phytotoxic. Orizalin and oxyfluorfen were tolerated satisfactorily. The other herbicides (simazine, thiazopyr, linuron + pendimethalin, isoxaben, tribenuron and glyphosate + diflufenican) showed variable responses. The tolerance of the trees was better before shooting than after active growing.
The following values have no corresponding Zotero field: periodical: CONGRESS 1997 - SOCIEDAD ESPANOLA DE MALHERBOLOGIA, PROCEEDINGS pub-location: DEPARTAMENTO HORTOFRUTICULTURA , BOTANICA I JARDINERIA ETSEA, UNIVERSITAT LLEIDA, 25198 LLEIDA, SPAIN
Keywords: diuron; norflurazone; Quercus ilex; Quercus suber; residual herbicides

Tree bark as a bioindicator of air pollution in Navarra, Spain - Santamaria, J M; Martin, A (Water, Air, & Soil Pollution, 1997)
During a two year research period from 1992 to 1993, samples of different species of trees were taken in 17 forest stands located in Navarra, Spain. From these samples, bark extracts were prepared in which the pH and the conductivity were measured. The health of the sampling trees was also evaluated by determining the degree of defoliation and decoloration of the canopies. The bark tissue analysis revealed the presence of an environmental acidity gradient that decreased from NW to SE. This coincides with the location of important sources of pollution and their course of transport and dispersion. On the other hand, in the samples of Quercus ilex a significant correlation between the pH and the defoliation levels (P<0.01, r = 0.62) was found. This fact reveals the potential usefulness of tree bark as a health bioindicator of trees.
Keywords: air pollution; Bioindicator; biomonitoring; Tree bark

Trichome density and its UV-B protective potential are affected by shading and leaf position on the canopy - Liakoura, V; Stefanou, M; Manetas, Y (Environmental and Experimental Botany, 1997)
In Olea europaea trichome density and UV-B absorbing compounds of leaf hairs and the lamina proper of leaves located in south-facing, north-facing and the internal of the canopy were positively correlated to the UV-B midday instant irradiance measured in September at these three different positions of the canopy. The correlation between these three parameters and the receiving photosynthetically active radiation (PAR), however, was weaker. In Quercus ilex, trichome density and its UV-B absorbing capacity were considerably higher in the exposed, south-facing leaves, compared to the deeply shaded ones; the UV-B absorbing capacity of the de-haired lamina, however, was the same. In the broad- leaved, alpine rosette of Verbascum speciosum, one could distinguish two areas on the leaves, one exposed and one shaded by the superimposed lamina. Although trichome density and the UV-B absorbing compounds of the de-haired leaf were the same in the two areas, the UV-B absorbing capacity of hairs was considerably increased in the exposed region. In V. speciosum, exposure induced also qualitative changes in the UV-B absorbance profile, apparently due to the formation of new flavonoid compounds absorbing maximally at 345-350 nm. In all other cases, the differences were mainly quantitative. The results support the postulate of a function of leaf hairs as a UV-B radiation screen and suggest that trichome density and/or its UV-B absorbing capacity may depend on irradiance during leaf development.
Keywords: leaf hairs; Olea europaea; phenolics; Quercus coccifera; Quercus ilex; uv-b radiation; verbascum speciosum

Trichome density and its UV-B protective potential are affected by shading and leaf position on the canopy - Liakoura, V.; Stefanou, M.; Manetas, Y. (Environmental and Experimental Botany, 1997)
In Olea europaea trichome density and UV-B absorbing compounds of leaf hairs and the lamina proper of leaves located in south-facing, north-facing and the internal of the canopy were positively correlated to the UV-B midday instant irradiance measured in September at these three different positions of the canopy. The correlation between these three parameters and the receiving photosynthetically active radiation (PAR), however, was weaker. In Quercus ilex, trichome density and its UV-B absorbing capacity were considerably higher in the exposed, south-facing leaves, compared to the deeply shaded ones; the UV-B absorbing capacity of the de-haired lamina, however, was the same. In the broad- leaved, alpine rosette of Verbascum speciosum, one could distinguish two areas on the leaves, one exposed and one shaded by the superimposed lamina. Although trichome density and the UV-B absorbing compounds of the de-haired leaf were the same in the two areas, the UV-B absorbing capacity of hairs was considerably increased in the exposed region. In V. speciosum, exposure induced also qualitative changes in the UV-B absorbance profile, apparently due to the formation of new flavonoid compounds absorbing maximally at 345-350 nm. In all other cases, the differences were mainly quantitative. The results support the postulate of a function of leaf hairs as a UV-B radiation screen and suggest that trichome density and/or its UV-B absorbing capacity may depend on irradiance during leaf development.
Keywords: leaf hairs; Olea europaea; phenolics; Quercus coccifera; Quercus ilex; uv-b radiation; verbascum speciosum

Una nueva técnica viverística para la introducción de plantones de DE QUERCUS SPP. EN CLIMA SECO Y SEMIÁRIDO - Vilagrosa, A; SEVA, J P; Valdecantos, a; HERNÁNDEZ, N; CORTINA, J; Bellot, J; Vallejo, V R (II Congreso Forestal Español, 1997)
We present a new technique to improve the establishment of Quercus spp. seedlings in dry and semiarid environments. It is based on the use of pre-germinated acorns transplanted in biodegradable nursery container which are transferred to the field befo re root pruning and upward root growth occurs. In this experiment we also tested the use of tree-shelters.
Keywords: bellotas pregerminadas (voyant); clima mediterráneo; plantones; Quercus spp.; supervivencia

Use of space and resources in a Mediterranean population of the butterfly Euphydryas aurinia - Munguira, M L; Martín, J; García-Barros, E; Viejo, J L (Acta Oecologica, 1997)
stract Population parameters of a central Spanish population of the marsh fritillary butterfly, Euphy- dryas aurinia (Rott.), were studied between 1990 and 1991. Numbers were very similar in the two study years, but adult emergence was delayed 15 days in the second year as a consequence of variation in weather conditions. The nectar sources used by adults were different in the two years and were correlated with the most abundant plants available during the flight period. Adult abundance was correlated with the pre- sence of the larval foodplant (Lonicera periclymenum) in open woodland and was higher where this habitat was mixed with open areas, where nectar sources abound. Estimates of male population numbers were higher than those of females, suggesting that males used wider ranges than females, or a higher residence rate for males. Nevertheless mobility did not differ significantly between the sexes. The conservation of the species in central Spain depends on maintaining patches of oak wood- lands, important for the presence of larval foodplants. Large numbers of the butterfly in the Natural Park study area are favoured by traditional management including charcoal production and extensive grazing by cattle and goats.
Keywords: conservation; lepidoptera; nymphalidae; population estimates; resource use; spatial distribution

Use of the isoprene algorithm for predicting the monoterpene emission from the Mediterranean holm oak Quercus ilex L.: Performance and limits of this approach - Ciccioli, Paolo; Fabozzi, Concetta; Brancaleoni, Enzo; Cecinato, Angelo; Frattoni, Massimiliano; Loreto, Francesco; Kesselmeier, Jürgen; Schäfer, Luise; Bode, Kirsten; Torres, Liberto; Fugit, Jean-Luc (Journal of Geophysical Research: Atmospheres, 1997)
The algorithm developed by Guenther et al. [1991] to describe the organic emission of isoprene-emitting plants has been used for predicting monoterpene emission from Quercus ilex L., an evergreen oak typical of the Mediterranean basin. The dependence of monoterpene emission on photosynthetically active radiation and temperature has been verified through laboratory experiments carried out on single leaves as well as through field measurements at branch level. While the algorithm describes well monoterpene emission under stationary state conditions, it is less accurate when rapid fluctuations of light and temperature take place. Because of this, the isoprene algorithm is capable of predicting the response of Quercus ilex L. with an accuracy better than ±25% only in 65% of the environmental situations experienced by the plant. Field and laboratory observations consistently indicate that temperature oscillations can be an important source for the discrepancies between predicted and observed values as they can generate bursts of emission with values twice as high as those predicted by the algorithm. Possible causes generating these effects are analyzed and critically discussed. In spite of the observed limitations, the isoprene algorithm can successfully describe the biogenic emission from Quercus ilex L., and its use is advantageous as it greatly simplifies regional and global emission models, especially if the light dependence of monoterpene emission is proven to be a widespread phenomenon.
Keywords: Biogenic emission; isoprene algorithm; monoterpene (voyant); Quercus ilex; Temperature

Use of the isoprene algorithm for predicting the monoterpene emission from the Mediterranean holm oak Quercus ilex L.: Performance and limits of this approach - Ciccioli, Paolo; Fabozzi, Concetta; Brancaleoni, Enzo; Cecinato, Angelo; Frattoni, Massimiliano; Loreto, Francesco; Kesselmeier, Jürgen; Schäfer, Luise; Bode, Kirsten; Torres, Liberto; Fugit, Jean-Luc (Journal of Geophysical Research: Atmospheres, 1997)
The algorithm developed by Guenther et al. [1991] to describe the organic emission of isoprene-emitting plants has been used for predicting monoterpene emission from Quercus ilex L., an evergreen oak typical of the Mediterranean basin. The dependence of monoterpene emission on photosynthetically active radiation and temperature has been verified through laboratory experiments carried out on single leaves as well as through field measurements at branch level. While the algorithm describes well monoterpene emission under stationary state conditions, it is less accurate when rapid fluctuations of light and temperature take place. Because of this, the isoprene algorithm is capable of predicting the response of Quercus ilex L. with an accuracy better than ±25% only in 65% of the environmental situations experienced by the plant. Field and laboratory observations consistently indicate that temperature oscillations can be an important source for the discrepancies between predicted and observed values as they can generate bursts of emission with values twice as high as those predicted by the algorithm. Possible causes generating these effects are analyzed and critically discussed. In spite of the observed limitations, the isoprene algorithm can successfully describe the biogenic emission from Quercus ilex L., and its use is advantageous as it greatly simplifies regional and global emission models, especially if the light dependence of monoterpene emission is proven to be a widespread phenomenon.
Keywords: Biogenic emission; isoprene algorithm; monoterpene (voyant); Quercus ilex; Temperature

Variabilidad de los factores de calidad para el corcho en plancha. - GONZÁLEZ ADRADOS, J R; GONZÁLEZ HERNÁNDEZ, J F; SIMÓN SERFATY, L; Adrados, L E Z; Hern, L E Z; Apdo, Serfaty Cifor-inia (II Congreso Forestal Español, 1997)
Main parameters affecting cork production and quality (thickness, apparent density, surface density, annual growth and porosity) are studied. Data from a sample of 105 pieces of cork (20 cm x 20 cm size) collected in seven different sites are analysed. Sites are considered as representative of the most common Spanish Quercus suber stands. Means and standard deviations of this parameters are presented for the different quality grades obtained by manual classification, focusing on the effect of grading on porosity and density. The effect of site factor on density and annual growth is also studied.
Keywords: Annual Growth; Cork; Cork Production; Cork quality; Density; Porosity; Quercus suber

Variaçáo da porosidade da cortiça ao longo do tronco dosobreiro - Lopes, Fernando; Pereira, Helena (II Congreso Forestal Español, 1997)
The within tree variation of cork quality has practical relevance when considering the methodology for estimating the quality of production using a field sampling. Samples are usually taken at breast height and an indication how quality at this level might relate to the overall average quality would help to improve estimates for the overall stand cork quality. The porosity of cork was analysed for whole stems. A total of 12 trees were evaluated, from six sites (Mora, Palma, Porto Alto, Grandola, Azaruja and Chamusca). The porosity was measured using image analysis techniques in tangential sections and in transverse sections. The cork for the different trees observed had different average porosities, ranging from 2.7% to 14.5% in the transverse section at b.h .. Within tree variatíon of cork porosity was found, with a average pattern of decreasing porosity within tree height. However a umque pattern of variation could not be established.
The following values have no corresponding Zotero field: periodical: II Congreso Forestal Español pub-location: Pamplona
Keywords: Cork; cork-oak; image analysis; Porosity; stem

Variaçáo da porosidade da cortiça ao longo do tronco dosobreiro - Lopes, Fernando; Pereira, Helena (II Congreso Forestal Español, 1997)
The within tree variation of cork quality has practical relevance when considering the methodology for estimating the quality of production using a field sampling. Samples are usually taken at breast height and an indication how quality at this level might relate to the overall average quality would help to improve estimates for the overall stand cork quality. The porosity of cork was analysed for whole stems. A total of 12 trees were evaluated, from six sites (Mora, Palma, Porto Alto, Grandola, Azaruja and Chamusca). The porosity was measured using image analysis techniques in tangential sections and in transverse sections. The cork for the different trees observed had different average porosities, ranging from 2.7% to 14.5% in the transverse section at b.h .. Within tree variatíon of cork porosity was found, with a average pattern of decreasing porosity within tree height. However a umque pattern of variation could not be established.
Keywords: Cork; cork-oak; image analysis; Porosity; stem

Variaçáo da porosidade da cortiça determinismo fenotípico - Fonseca, Fortunato M. A.; Louzada, José Luis P. C.; Gomes, César A. M. (II Congreso Forestal Español, 1997)
Analyses were made of the variation in the porosity of cork collected from 100 trees at the BHD level and in 30 trees, with reproduction cork collected at three levels of height with a fourth level of virgin cork. Despite verifying the recognizable and elevated variability (1 to 10) among trees, it (44%) is greatly exceeded by the internal variability (56%) of the porosity of cork in the individuals, without a presumable systematization with the growth or funcionality. The phenotype determinism, within the reproduction corks for the number of pores is relatively elevated (R2 =40% to 60%) but already reduced (R2 =20% to 30%) for the porosity. On the other hand, there doesn't exist any such type of phenotypical determinism between the poro sities of reproduction cork anf of virgin cork, something which also supports the hypothesis of elevated abnormalities or reaction in the formation of reproduction cork.
The following values have no corresponding Zotero field: periodical: II Congreso Forestal Español issue: 1982 pub-location: Pamplona
Keywords: Cork; phenotypical determinismo; Porosity; variation

Variaçáo da porosidade da cortiça determinismo fenotípico - Fonseca, Fortunato M A; Louzada, José Luis P C; Gomes, César A M (II Congreso Forestal Español, 1997)
Analyses were made of the variation in the porosity of cork collected from 100 trees at the BHD level and in 30 trees, with reproduction cork collected at three levels of height with a fourth level of virgin cork. Despite verifying the recognizable and elevated variability (1 to 10) among trees, it (44%) is greatly exceeded by the internal variability (56%) of the porosity of cork in the individuals, without a presumable systematization with the growth or funcionality. The phenotype determinism, within the reproduction corks for the number of pores is relatively elevated (R2 =40% to 60%) but already reduced (R2 =20% to 30%) for the porosity. On the other hand, there doesn't exist any such type of phenotypical determinism between the poro sities of reproduction cork anf of virgin cork, something which also supports the hypothesis of elevated abnormalities or reaction in the formation of reproduction cork.
Keywords: Cork; phenotypical determinismo; Porosity; variation

Variation for male success in Holm oak, a monoecious and a highly self-incompatible species - Yacine, A; Valero, M; Bouras, F (SEVENTH INTERNATIONAL SYMPOSIUM ON POLLINATION - POLLINATION: FROM THEORY TO PRACTISE, 1997)
In natural populations, male success is determined by pre-and post-pollination events. The latter could be separated to pre-and post-fertilization stages at which different mechanisms control pollen donor success. It is currently assumed that there is a direct relationship between pollen tube growth rapidity and fertilization ability. In this study, pollination experiments were conducted on a Helm oak (Quercus ilex) population to test male success. Pollen was used in two ways (1) as a single source and (2) mixed with the self pollen of the recipient. We analyzed differences between pollen donors at the prezygotic level by evaluating the relative proportions of the pollen tube presence in the style in comparison to those on the stigma and likewise between the style and the ovary, on five different dates after pollination. At the post-zygotic level, male success was measured as the proportion of fertilized ovules relative to pollinated flowers and as seed sired relative to fertilized ovules. At the pre-and post-zygotic level there were statistically significant differences between recipients that are however not significant between donors. In Quercus species pollination occurs before the ovules develop; our results indicate that different arrangements between pollen tube growth and ovule development may occur. Self-incompatibility may be one factor in differential recipient success through the interactions between out and self-incompatible pollen.
Keywords: fertilization; male success; pollen tube; pollination; Quercus ilex

Variation for male success in Holm oak, a monoecious and a highly self-incompatible species - Yacine, A.; Valero, M.; Bouras, F. (SEVENTH INTERNATIONAL SYMPOSIUM ON POLLINATION - POLLINATION: FROM THEORY TO PRACTISE, 1997)
In natural populations, male success is determined by pre-and post-pollination events. The latter could be separated to pre-and post-fertilization stages at which different mechanisms control pollen donor success. It is currently assumed that there is a direct relationship between pollen tube growth rapidity and fertilization ability. In this study, pollination experiments were conducted on a Helm oak (Quercus ilex) population to test male success. Pollen was used in two ways (1) as a single source and (2) mixed with the self pollen of the recipient. We analyzed differences between pollen donors at the prezygotic level by evaluating the relative proportions of the pollen tube presence in the style in comparison to those on the stigma and likewise between the style and the ovary, on five different dates after pollination. At the post-zygotic level, male success was measured as the proportion of fertilized ovules relative to pollinated flowers and as seed sired relative to fertilized ovules. At the pre-and post-zygotic level there were statistically significant differences between recipients that are however not significant between donors. In Quercus species pollination occurs before the ovules develop; our results indicate that different arrangements between pollen tube growth and ovule development may occur. Self-incompatibility may be one factor in differential recipient success through the interactions between out and self-incompatible pollen.
The following values have no corresponding Zotero field: periodical: SEVENTH INTERNATIONAL SYMPOSIUM ON POLLINATION - POLLINATION: FROM THEORY TO PRACTISE issue: 437 pub-location: PO BOX 500, 3001 LEUVEN 1, BELGIUM
Keywords: fertilization; male success; pollen tube; pollination; Quercus ilex

Vegetative compatibility and pathogenicity of Diplodia mutila isolates on oak - Ragazzi, A. (European journal of forest pathology, 1997)
Forty isolates of Diplodia mutila, a dieback agent on oaks were characterized by their capacity to produce heterokaryons, by their vegetative compatibility, and by their pathogenicity tests on Quercus cerris. The forty isolates were collected from Quercus cerris, Quercus frainetto, Quercus ilex, Quercus pubescens, Quercus robur and Quercus suber in different regions in Italy. Three nit mutants (nit,, nit, and nit,) were identified with different nitrogen sources: sodium nitrite, sodium nitrate, uric acid, ammonium tartrate and hypoxanthine. O n the two nutrient media employed, a potato dextrose agar (PDA) medium with chlorate (PDC), and a minimal agar medium with chlorate (MMC), isolates obtained from Q. cerris Felded the greatest number of mutants: 254 on PDC (out of a total of 583) and 190 on MMC (out o a total of 440). Nine vegetative compatibility grou s (VCGs) were identified. There was a strong association between these VCGs and host species. Alfisolates tested except one from Q. cerris were pathogenic.
Keywords: diplodia mutila; disease (voyant); nit mutants; Pathogenicity; Quercus; vegetative compatibility

Vertebrate predation on Holm Oak, Quercus ilex, acorns in a fragmented habitat: effects on seedling recruitment - Santos, T.; Tellería, J. L. (Forest Ecology and Management, 1997)
Rodent and avian consumption of Holm Oak, Quercus ilex, acorns were examined in central Spain during two high-production seasons, 1990-1991 and 1993-1994, in 1 and 3 large stands and in 6 and 10 small stands (0.2-12 ha) respectively, to study the effects of vertebrate predation on seedling recruitment. Previous data indicate that wood mouse abundance is much higher in small stands. Tree size, frequency of acorn-bearing oaks and acorn abundance were similar in the two sizes of forest stands. Overall acorn consumption was 33.7 times higher in the small stands compared to that in the large stands in 1991, and 3.1 times larger in 1994. Consumption of acorns by mice in the small stands was 49 and 95 times greater than that by birds in the first and second year, respectively. Seedling recruitment was significantly higher in the large stands in both study seasons. Regeneration by ramets was roughly similar in small and large stands in both seasons. Thus, predation by mice was apparently responsible for the failure of sexual reproduction in the small stands. The results suggest that vegetative regeneration might be the prevalent reproductive method of Holm Oaks in small forest tracts.
Keywords: acorns; Forest fragmentation; oak; Seedling; Vertebrate predation

Visualization of the cytoskeleton within the secondary vascular system of hardwood species - Chaffey, N J; Barnett, J R; Barlow, P W (Journal of Microscopy, 1997)
A single fixation technique has been devised to demonstrate localization of α-tubulin (for microtubules) and F-actin (for microfilaments) within the secondary vascular system of hardwood trees by indirect immunofluorescence microscopy using butyl-methylmethacrylate-embedded material. Application of this technique to problems of cytomorphogenesis during secondary growth and its versatility are demonstrated with the hardwood species Aesculus hippocastanum L., Salix viminalis L., S. burjatica Nazarov × S. viminalis L., Hedera helix L., Acer platanoides L., Platanus sp., Quercus ilex L. and Liriodendron tulipifera L., and in the softwood Pinus pinea L. The methods employed have considerable scope for advancing knowledge of the role of the cytoskeleton in differentiation within the secondary vascular system of woody species.
Keywords: a -tubulin; a-Tubulin; cytoskeleton; embedment; f-actin; hardwood trees; immunofluorescence microscopy; indirect; indirect immunofluorescence microscopy; microfilaments; microtubules; removable; removable embedment; secondary vascular tissue; vascular cambium

The voluntary intake and rumen digestion by grazing goats and sheep of a low-quality pasture from a semi-arid land - Alcaide, E M; García, M A; Aguilera, J F (Livestock Production Science, 1997)
An experiment was carried out in late autumn with goats and wethers fitted with permanent ruminal cannulae, grazing in a semi-arid area of South Spain. Shrubs were the most available plant species, although natural vegetation also included trees and grasses. In general, the dominant species of the available vegetation accounted for the highest proportion in the selected diet. Similar proportion and species of grasses were found in the pasture selected by goats and wethers, whereas interspecies differences were observed regarding the selection of shrubs and tree species. Crude protein content was similar in selected diets by goats and sheep, but a higher unavailable N proportion was found for sheep (27.1 and 30.0% of total N for goats and sheep, respectively). Digestibility of forage selected was higher for goats than for wethers. Voluntary intake was significantly (P < 0.05) higher in goats than in sheep; the metabolizable energy intake for goats was higher than their maintenance requirements but failed to meet maintenance needs for wethers. Fermentative rumen activity was moderate and similar for goats and sheep. No interspecies differences were found in rumen fermentation parameters except for molar proportions of acetic and propionic acid and for acetic/propionic ratio, which were significantly higher in wethers. The degradation rate tended to be faster in goats, whereas potential and effective degradability tended to be similar in goats and sheep.
Keywords: Goats; intake; rumen fermentation; semi-arid land; Sheep

The voluntary intake and rumen digestion by grazing goats and sheep of a low-quality pasture from a semi-arid land - Alcaide, E. M.; Garcıa, M. A.; Aguilera, J. F. (Livestock Production Science, 1997)
An experiment was carried out in late autumn with goats and wethers fitted with permanent ruminal cannulae, grazing in a semi-arid area of South Spain. Shrubs were the most available plant species, although natural vegetation also included trees and grasses. In general, the dominant species of the available vegetation accounted for the highest proportion in the selected diet. Similar proportion and species of grasses were found in the pasture selected by goats and wethers, whereas interspecies differences were observed regarding the selection of shrubs and tree species. Crude protein content was similar in selected diets by goats and sheep, but a higher unavailable N proportion was found for sheep (27.1 and 30.0% of total N for goats and sheep, respectively). Digestibility of forage selected was higher for goats than for wethers. Voluntary intake was significantly (P < 0.05) higher in goats than in sheep; the metabolizable energy intake for goats was higher than their maintenance requirements but failed to meet maintenance needs for wethers. Fermentative rumen activity was moderate and similar for goats and sheep. No interspecies differences were found in rumen fermentation parameters except for molar proportions of acetic and propionic acid and for acetic/propionic ratio, which were significantly higher in wethers. The degradation rate tended to be faster in goats, whereas potential and effective degradability tended to be similar in goats and sheep.
Keywords: Goats; intake; rumen fermentation; semi-arid land; Sheep

14 - Carbon Metabolism and Plant Growth under Elevated CO2 in a Natural Quercus ilex L. “Macchia” Stand - Scarascia-Mugnozza, Giuseppe E; Angelis, Paolo De; Matteucci, Giorgio; Kuzminsky, Elena (Carbon Dioxide, Populations, and Communities, 1996)
Publisher Summary This chapter examines the impact of long-term exposure to elevated CO2 concentration in a natural Mediterranean community dominated by Quercus ilex (high "macchia"). The research emphasizes on measurements of carbon metabolism and light energy utilization by the leaves to assess the physiological responses that subtend growth rather than just measuring short-term biomass increments at the tree level alone. Given the relevance of the Mediterranean woodland communities from an economical and environmental perspective, it is critical to be able to predict the possible effects of global change on these ecosystems and to eventually adopt adequate mitigation strategies. The interaction between carbon metabolism and biomass partitioning in woody plants is also regulated by nutrient availability. In the nutrient-limited Mediterranean environment, a CO2 increase may in part relieve this limitation by a greater efficiency of nutrient utilization, especially in tree species, characterized by a large proportion of their biomass allocated to components with low nutrient cost. These limitations are likely to moderate the responses of plants and communities to a global change, particularly to increases in atmospheric CO2 and biosphere warming. After a three-year period, the community responses to elevated CO2 indicate a wide range of acclimation processes by tree and shrub species in relation to their different ecological strategies.
Keywords: acclimation processes (PG); biomass allocation; carbon metabolism; Elevated CO2; long-term exposure; mediterranean macchia

Aboveground litter production and bioelement potential return in an evergreen oak (Quercus rotundifolia) woodland near Salamanca (Spain) - Martin, A; Gallardo, J F; Santa Regina, I (Ann. For. Sci., 1996)
Total aboveground production of trees has been determined in a Quercus rotundifolia evergreen oak woodland developed over a chromic Luvisol. The woodland is located close to the city of Salamanca (central-western Spain). Litter fall occurs throughout the year, with a maximum from April to June owing to leaf fall. Mean litter production is 1.9 Mg ha-1 year-1, although variations from year to year are observed, mostly due to water stress in summer. The mean area of influence of litter fall of each tree is about 4 m outside the crown shadow and the leaf percentage (55%) over the total aboveground litter production shows that the system is mature. Tree inflorescences are found to have the highest concentration in bioelements, although the latter are mostly returned through the leaves (with the exception of K).
Keywords: biogeochemical cycles; evergreen oak; litter fall; potential return of bioelements; Quercus rotundifolia Lam

Alterações estruturais da base de estacas de sobreiro (Quercus suber L.) em enraizamento, após escurecimento e AIB - Ribeiro, M M A; Amâncio, S; Quilhó, T (Simpósio de Propagação Vegetativa de Espécies Lenhosas, Castelo Branco, 18 a 20 de Outubro, 1996)
Estacas em enraizamento, retiradas de jovens plantas de sobreiro com 7 meses, foram utilizadas na recolha de amostras para acompanhamento anatomo-histológico das modificações estruturais da sua base. As plantas-mãe foram submetidas durante um mês a um pré-tratamento de escurecimento, que consistiu no envolvimento da parte do caule correspondente à futura base da estaca por uma banda preta. Em metade das plantas sujeitas ao escurecimento aplicou-se auxina (AIB em pó, na concentração de 0,5%) antes da colocação da banda preta. Para a montagem do ensaio de enraizamento, as estacas foram preparadas com cerca de 7 cm e, em cada grupo dos pré-tratamentos prévios das plantas mãe (só escurecimento ou escurecimento e AIB), metade foram tratadas com AIB na mesma formulação e dosagem. Realizaram-se seis colheitas de material (base das estacas em enraizamento), ao longo do mês que se seguiu ao início do ensaio, para posterior observação de cortes histológicos. No dia 0 observaram-se diferenças em relação à testemunha (não submetida a escurecimento), especialmente ao nível da periderme e do xilema. Até ao dia 20 as diferenças estruturais das estacas submetidas ao tratamento prévio de escurecimento foram-se acentuando, com alteração da disposição normal dos tecidos e aparecimento, por vezes abundante, de callus. Outra alteração ocorreu ao nível do anel de fibras perivasculares que rodeia o floema, que começou a evidenciar rupturas. No tratamento que incluía o escurecimento e a aplicação de AIB na banda preta surgiram, a partir do dia 3, descontinuidades nesse anel que se acentuaram ao longo do tempo, até que a partir do dia 14 essa estrutura praticamente deixou de existir. A partir desse dia e especialmente no dia 20, observou-se uma grande proliferação das células de floema e córtex, em particular as células parenquimatosas e ainda alteração ao nível do câmbio que deixou de ser nítido e único. A aplicação de AIB à base da estaca antes de esta ser posta a enraizar não conduziu a diferenças tão evidentes como o tratamento de escurecimento. Para todos os tratamentos efectuados as modificações surgiram primeiro na zona do nó e só depois na zona do entrenó.
Keywords: anatomia; Enraizamento; estacas; propagação vegetativa; Quercus suber L.; sobreiro

Annual cork-ring width variability of Quercus suber L. in relation to temperature and precipitation (Extremadura, southwestern Spain) - Caritat, A; Molinas, M; Gutiérrez, E (Forest Ecology and Management, 1996)
A 14 year sequence of cork-ring width chronology is correlated with rainfall and temperature data. Cork specimens were obtained from three cork peel samplings carried out in 1989, 1991 and 1993 from a cork ‘dehesa’ in Ckeres, Spain. Average width of cork-rings varied between 2.05 and 4.37 mm. The cork-ring width chronologies of the three peel-off samplings show definite agreement patterns. Differences in ring width in years of greater and lesser growth are clearly marked. Correlation between ring width and rainfall indicates that the rain periods with the greatest influence on cork growth are those occurring from November to June, followed by those from November to September. Temperature, on the other hand, shows a negative correlation with cork growth, except during the coldest months and the months of April and September when temperature possibly has a crucial influence on phellogen activation.
Keywords: climatic fluctuations; cork growth; cork-oak; cork-ring chronology; Quercus suber L.

Annual cork-ring width variability of Quercus suber L. in relation to temperature and precipitation (Extremadura, southwestern Spain) - Caritat, A.; Molinas, M.; GUTIÉRREZ, E. (Forest Ecology and Management, 1996)
A 14 year sequence of cork-ring width chronology is correlated with rainfall and temperature data. Cork specimens were obtained from three cork peel samplings carried out in 1989, 1991 and 1993 from a cork ‘dehesa’ in Ckeres, Spain. Average width of cork-rings varied between 2.05 and 4.37 mm. The cork-ring width chronologies of the three peel-off samplings show definite agreement patterns. Differences in ring width in years of greater and lesser growth are clearly marked. Correlation between ring width and rainfall indicates that the rain periods with the greatest influence on cork growth are those occurring from November to June, followed by those from November to September. Temperature, on the other hand, shows a negative correlation with cork growth, except during the coldest months and the months of April and September when temperature possibly has a crucial influence on phellogen activation.
Keywords: climatic fluctuations; cork growth; cork-oak; cork-ring chronology; Quercus suber L.

Are ecophysiological responses influenced by crown position in cork-oak? - Oliveira, G; Werner, C; Correia, O (Ann. For. Sci., 1996)
Montados and dehesas of Quercus ilex and Quercus suber occupy large areas in the Iberian Peninsula and are characterized by a low-density tree cover. The variability of responses within tree canopies in such open stands has been little studied. We investigated the variation of stomatal conductance within the crown of a cork-oak (Q suber L), by studying its diurnal and seasonal courses at two different heights and four directions within the canopy. Height did not strongly affect leaf response, as a consequence of the crown structure. Differences were found in microclimatic conditions and maximum stomatal conductance among directions. However, overall daily stomatal conductance was similar among different crown sections, suggesting that leaves develop different mechanisms to accomodate the microclimatic constraints which affect the particular position they occupy in the crown of cork-oak.
Keywords: cork-oak; isolated tree; microclimate; Stomatal conductance; within-crown variability

Are ecophysiological responses influenced by crown position in cork-oak? - Oliveira, G; Werner, C; Correia, O (Ann. For. Sci., 1996)
Montados and dehesas of Quercus ilex and Quercus suber occupy large areas in the Iberian Peninsula and are characterized by a low-density tree cover. The variability of responses within tree canopies in such open stands has been little studied. We investigated the variation of stomatal conductance within the crown of a cork-oak (Q suber L), by studying its diurnal and seasonal courses at two different heights and four directions within the canopy. Height did not strongly affect leaf response, as a consequence of the crown structure. Differences were found in microclimatic conditions and maximum stomatal conductance among directions. However, overall daily stomatal conductance was similar among different crown sections, suggesting that leaves develop different mechanisms to accomodate the microclimatic constraints which affect the particular position they occupy in the crown of cork-oak.
Keywords: cork-oak; isolated tree; microclimate; Stomatal conductance; within-crown variability

Assessment of biophysical vegetation properties through spectral decomposition techniques - Hurcom, S J; Harrison, A R; Taberner, Malcolm (Remote sensing of environment, 1996)
This article demonstrates the use of spectral decomposi- tion for analyzing the spectral response of different semi- arid vegetation species found throughout Mediterranean Europe. Using this technique, it is possible to decompose a spectral data set into a smaller number of significant factors that represent the key variables affecting vegeta- tion spectral response. The results presented here show how spectral decomposition can be used to determine the intrinsic number and identity of the significant factors affecting the multispectral response. For the dataset inves- tigated here, which comprises field spectra recorded over 1130 wavelengths, using a GER single field-of-view IRIS (SIRIS) spectroradiometer, it was found that a combina- tion of just four factors was responsible for the majority of spectral variance. Interpretation of these factors was carried out by graphical analysis, stepwise regeneration of the original spectra, and correlation with biophysical data. Considering the identity of these factors, it was found that the second most significant factor (factor 2) was strongly related to the proportion of directly irradi- ated green leaves within the field-of-view of the spectrora- diometer. In addition, it was found that the fourth most significant factor (factor 4) provided a good summary of the spectral response of the different samples in the region of strong chlorophyll absorption. This demonstrates the possibility of using spectral decomposition techniques, particularly in environments dominated by spectrally similar vegetation classes, to model the mixed spectral population as mixtures of fundamental biophysical pa- rameters rather than as mixtures of the classes themselves.
Keywords: factor analysis; leaf reflectance; spectral decomposition; surface leaf area (voyant)

Assessment of mineral nutrition of cork oak through foliar analysis - Robert, Bénédicte; Bertoni, Georges; Sayag, Daniel; Masson, Philippe (Communications in Soil Science and Plant Analysis, 1996)
Abstract The changes in the mineral nutrient content of the leaves of an evergreen species, the cork oak (Quercus suber L.), were investigated to assess the possibilities of a diagnosis of the mineral nutrition of this forest species. A comprehensive pattern of change in the leaf contents of N, P, and Ca was then put forward from the data obtained. Among the time intervals that are most favorable to analyses, the end of the vegetative rest period, in January, was investigated more precisely. The variation coefficients of the leaf contents measured tree by tree were determined for a number of nutrients (N, P, K, Ca, Mg, Fe, Cu, Zn, Mn, B, Al, and Cl). The foliar analyses carried out on 7? to 10?month old leaves in stands submitted to various forest management practices led to the characterization of significant differences in P, Ca and Mn leaf contents in relation to the treatments applied.
Keywords: Cork oak; leaf content; Mineral nutrition; Quercus suber

Behaviour of different horticultural species in phytotoxicity bioassays of bark substrates - Ortega, M C; Moreno, M T; Ordovas, J; Aguado, M T (Scientia Horticulturae, 1996)
The use of forestry wastes (barks, sawdust, wood chips) as potting media components can involve serious problems of toxicity that must be evaluated. Evaluation methods may consist of analytic techniques to detect and quantify phytotoxic molecules, or rapid bioassays, with low technical requirements, using species sensitive to the toxic elements. These bioassays should be able to predict plant behaviour in real growing conditions. In this study we used as substrate cork oak bark (Quercus suber L.). This material, like other forestry wastes, contains phytotoxic phenolic compounds which can be washed out with hot water. The phenolic content of cork (C) and washed cork (WC) was measured, and two germination bioassays were carried out with eight horticultural species. In the first, aqueous extracts of cork (C) and washed cork (WC) obtained with water at 15°C and 70°C were used, and the second was done directly on the substrates. In addition, a seedling growing test was carried out with the same species. We concluded that tomato and lettuce are the most sensitive species, and the direct test on the substrate is recommended owing to its simplicity and close correspondence to growing conditions.
Keywords: Barks; Bioassay; Cork; Horticultural; Phenolic acids; Phytotoxicity; substrate

Biomasse végétale et production fourragère sur terres de parcours sous climat méditerranéen ou tropical sec - Etienne, M. (Ann. Zootech., 1996)
After an overview on the regions concerned and a review of the concepts of rangeland, fodder production and pastoral value, the vegetation, productivity and potential improvement of mediterranean and dry tropical rangelands are assessed. The main range vegetation types are described and characterised by their physiognomy, plant morphology and main ecological constraints. Rangeland fodder production is assessed by analysing the main limiting production factors and by comparing the intra and interannual variations of fodder productivity and quality. Vegetation dynamics of some common range types is discussed according to range management techniques (fire, cutting, cultivation) or livestock management criteria (stocking rate, type of animal, fodder system). Some examples of range improvements applied to contrasted ecological and socio-economical conditions are discussed by analysing their impact on soil, fodder species, vegetation dynamics and range management. To conclude, the need of splitting from fodder production models to range management models is evoked.
Keywords: dynamique de la végétation (voyant); gestion des ressources; Parcours; production fourragère; qualité nutritionnelle

Biomasse végétale et production fourragère sur terres de parcours sous climat méditerranéen ou tropical sec - Etienne, M (Ann. Zootech., 1996)
After an overview on the regions concerned and a review of the concepts of rangeland, fodder production and pastoral value, the vegetation, productivity and potential improvement of mediterranean and dry tropical rangelands are assessed. The main range vegetation types are described and characterised by their physiognomy, plant morphology and main ecological constraints. Rangeland fodder production is assessed by analysing the main limiting production factors and by comparing the intra and interannual variations of fodder productivity and quality. Vegetation dynamics of some common range types is discussed according to range management techniques (fire, cutting, cultivation) or livestock management criteria (stocking rate, type of animal, fodder system). Some examples of range improvements applied to contrasted ecological and socio-economical conditions are discussed by analysing their impact on soil, fodder species, vegetation dynamics and range management. To conclude, the need of splitting from fodder production models to range management models is evoked.
Keywords: dynamique de la végétation (voyant); gestion des ressources; Parcours; production fourragère; qualité nutritionnelle

Breeding patterns of the Great Tit (Parus major) in a pine plantation and a holm oak forest in a Mediterranean region (southern Spain) - Catalan, R M; Haeger, J F (Revue d'Ecologie la Terre et la Vie, 1996)
This study compares breeding patterns of nestbox-breeding Great Tits (Parus major) between two adjacent forest habitats: a pine plantation and a Mediterranean helm oak Quercus rotundifolia forest. Breeding density increased in both forests when nestbox density was raised. The breeding season started earlier in the pinewood, but tended to end at the same time in both habitats. Reproductive effort was higher in the plantation as reflected in egg volume rather than clutch size. Time of season had an effect on clutch size but not on the size of the eggs which remained constant throughout the breeding season. Breeding success was associated with habitat, with both the number of fledglings and their weight being higher in the pinewood. These parameters showed a seasonal trend in the pinewood but not in the helm oak forest. Our results show that Great Tit achieves a higher reproductive performance in the pinewood in spite of its recent settling in this habitat.
APS
Keywords: breeding pattenrns; great tits; Mediterranean; nest-box; Parus major; pine plantation; Quercus ilex

Carbon isotope discrimination in Quercus ilex resprouts after fire and tree-fell - Fleck, Isabel; Grau, Daniel; Sanjosé, M; Vidal, D (Oecologia, 1996)
Ecophysiological differences related to photo- synthesis were compared in holm oak Quercus ilex leaves from undisturbed holm-oak vegetation, resprouts after fire and resprouts after tree-fell. No significant dif- ferences in any parameter measured were observed be- tween the two kinds of resprout throughout the first growing season following disturbance. Resprouting leaves showed lower carbon isotope discrimination (A) and intercellular CO 2 concentration (Pi), and higher pho- tosynthesis, leaf conductance and transpiration rates than leaves from undisturbed stands. Nitrogen, soluble protein content and ribulose bisphosphate carboxylase (RuBP- Case) activity were 88%, 96% and 45% higher respec- tively, in both kinds of resprout. The results indicate that photosynthetic capacity, rather than stomatal conduc- tance, is the limiting factor in photosynthesis in re- sprouts. Chlorophyll content and chlorophyll a/b ratio did not differ between resprouts and undisturbed leaves, indicating that the observed differences were not a result of differences in light environment during leaf develop- ment. Leaf mass per area (LMA), was 80% higher in the resprouts, and was negatively related (r= -0,86) to A and positively related (r=0.87) to N content. Enhanced car- bon assimilation after disturbances resulted in higher wa- ter use efficiency, as indicated by lower A values in the resprouts. We conclude that the cause of defoliation was not relevant in the physiology of the resprouts, suggest- ing the importance of underground organs.
Keywords: carbon isotope discrimination; Fire and tree-fell resprouts; Gas exchange; RuBPCase activity

Carbon isotope discrimination in Quercus ilex resprouts after fire and tree-fell - Fleck, Isabel; Grau, Daniel; Sanjose, M.; Vidal, D. (Oecologia, 1996)
Ecophysiological differences related to photo- synthesis were compared in holm oak Quercus ilex leaves from undisturbed holm-oak vegetation, resprouts after fire and resprouts after tree-fell. No significant dif- ferences in any parameter measured were observed be- tween the two kinds of resprout throughout the first growing season following disturbance. Resprouting leaves showed lower carbon isotope discrimination (A) and intercellular CO 2 concentration (Pi), and higher pho- tosynthesis, leaf conductance and transpiration rates than leaves from undisturbed stands. Nitrogen, soluble protein content and ribulose bisphosphate carboxylase (RuBP- Case) activity were 88%, 96% and 45% higher respec- tively, in both kinds of resprout. The results indicate that photosynthetic capacity, rather than stomatal conduc- tance, is the limiting factor in photosynthesis in re- sprouts. Chlorophyll content and chlorophyll a/b ratio did not differ between resprouts and undisturbed leaves, indicating that the observed differences were not a result of differences in light environment during leaf develop- ment. Leaf mass per area (LMA), was 80% higher in the resprouts, and was negatively related (r= -0,86) to A and positively related (r=0.87) to N content. Enhanced car- bon assimilation after disturbances resulted in higher wa- ter use efficiency, as indicated by lower A values in the resprouts. We conclude that the cause of defoliation was not relevant in the physiology of the resprouts, suggest- ing the importance of underground organs.
Keywords: carbon isotope discrimination; Fire and tree-fell resprouts; Gas exchange; RuBPCase activity

Characteristics of internal porosity of cork container media - Ordovas, J; Carmona, E; Moreno, M T; Ortega, M C (HORTSCIENCE, 1996)
The structure of cork (Quercus suber L.) bark presents a series of characteristics, suggesting that internal porosity is partly occluded. This study determined the porosity in the waste cork industry (C) and when such waste product had been composted during 4 (CC-4), 7 (CC-7), and 10.5 months (CC-10.5). The particle density of the intact and finely ground material differed significantly in all particle size ranges larger than 0.5 mm. The porosity of the cork substrates ranged from 80% to 94% of the total volume, according to granulometry and the degree of decomposition. However, large particles and less decomposed material with a high porosity had up to 10% of the total volume as occluded pores. The material's effective porosity varied slightly between the various particle sizes and degrees of decomposition, which ranged between 80% and 89%, having an average value of 85%. The ash content was highly correlated with the particle density of the finely ground material. Nevertheless, and due to occluded porosity, we cannot estimate the `'effective porosity'' from the ashes; therefore, we must resort to techniques that involve the displacement of a fluid, such as liquids or gas pycnometry or submersion.
Keywords: ash content; effective porosity; particle density; total porosity

Characteristics of internal porosity of cork container media - Ordovas, J.; Carmona, E.; Moreno, M. T.; Ortega, M. C. (HORTSCIENCE, 1996)
The structure of cork (Quercus suber L.) bark presents a series of characteristics, suggesting that internal porosity is partly occluded. This study determined the porosity in the waste cork industry (C) and when such waste product had been composted during 4 (CC-4), 7 (CC-7), and 10.5 months (CC-10.5). The particle density of the intact and finely ground material differed significantly in all particle size ranges larger than 0.5 mm. The porosity of the cork substrates ranged from 80% to 94% of the total volume, according to granulometry and the degree of decomposition. However, large particles and less decomposed material with a high porosity had up to 10% of the total volume as occluded pores. The material's effective porosity varied slightly between the various particle sizes and degrees of decomposition, which ranged between 80% and 89%, having an average value of 85%. The ash content was highly correlated with the particle density of the finely ground material. Nevertheless, and due to occluded porosity, we cannot estimate the `'effective porosity'' from the ashes; therefore, we must resort to techniques that involve the displacement of a fluid, such as liquids or gas pycnometry or submersion.
The following values have no corresponding Zotero field: pub-location: 701 NORTH SAINT ASAPH STREET, ALEXANDRIA, VA 22314-1998 publisher: AMER SOC HORTICULTURAL SCIENCE
Keywords: ash content; effective porosity; particle density; total porosity

Characterization of cells in cork - Pina, P; FORTES, M A (JOURNAL OF PHYSICS D-APPLIED PHYSICS, 1996)
Various topological and metric properties of the cells in the phelogen of the cork oak have been measured in tangential sections of cork by image analysis methods. These include the fractions f(i) of cells with i sides (i-cells), the fractions f(ik), of adjacencies between i- and k-cells and various distributions of cell areas in relation to topology.

Composition and metabolizable energy of feed used by fallow deer (Dama dama) in a coastal Mediterranean ecosystem - Poli, B M; Focardi, S; Tinelli, A (Small Ruminant Research, 1996)
Data on the impact of a population of about 1000 (spring estimate) fallow deer (Dama &ma) on eight shrubs and mono- and dicotyledonous plants were collecred in a coastal Mediterranean environment from December 1990 to March 1992. Four species of shrubs (Cistus salvifoiius, Phillyrea larifolia, Rubus ulmifolius. Quercus ibex) and mixed graminoids were preferentially consumed. In autumn-winter the acorns of several species, Q. cerris and Q. ilex in particular, were also consumed. We determined the chemical composition, in vivo digestibility coefficients and metabolizable energy content of the feed. On average, R. ulmifolius had the lowest fibre content (18% DM) and the highest protein content (12% DM), organic matter digestibility (59%) and metabolizable energy value (2083 kcal ME kg- ’ DM). C. saluifolius, P. fafifolia and mixed graminoids did not differ significantly in organic matter digestibility (OMD) and nutritive value (I 801, 1765 and 1557 kcal ME kg-’ DM, respectively), while Q. ilex had the lowest nutrient estimates with 32% OMD and 1362 kcal ME kg-’ DM. Forage quality traits usually peaked in spring and autumn. Metabolizable energy was positively correlated with protein, neutral detergent fibre and N-free extractives contents, and negatively correlated with the acid detergent fibre content. Acorns were generally highly digestible; in particular, the seed of Q. farniu and Q. ilex showed 80% and 83% OMD, respectively. In a Mediterranean environment the summer seems the most critical season for fallow deer. The results of this work are important for assessing the carrying capacity of wild Mediterranean ecosystems for fallow deer.
Keywords: digestibility; Fallow deer; Feed quality; in vitro; Mediterranean ecosystems

Decomposition of mediterranean leaf litters: A microcosm experiment investigating relationships between decomposition rates and litter quality - Cortez, J; Demard, J M; Bottner, P; Jocteur Monrozier, L (Soil Biology and Biochemistry, 1996)
he decomposition of four mediterranean species leaf litter (Sessile oak, Quercus petraea L.; Holm oak, Quercus ibex L.; Sweet chestnut, Castanea satiua Mill and beech, Fagus syluatica L.) was studied for 90 days under controlled conditions. Respiration and litter mass loss were measured in three types of microcosms: (1) Soil only; (2) Soil + l-y old litter and (3) Soil + l-y old litter + newly senescent litter (freshly fallen). Variations in chemical composition of the litters were determined before and after incubation by the pyroanalysis method. For newly senescent litters decomposition rates per day Kco, (calculated from CO, release) and K, (calculated from mass losses) fitted to the first order exponential decay decreased as follows: sessile oak (Kc,_,, = 0.0043; K, = 0.0049) > holm oak (Km, = 0.0031; K, = 0.0040) = beech (&o~ = 0.0030; K, = 0.0030) > sweet chestnut (Kc% = 0.0001; K,, = non- significant regression); For l-y old litters sweet chestnut (Ko,, = O.oo40, K, = 0.0065) > sessile oak (KEO, = 0.0035; K, = 0.0039) > beech (Kcc,, = 0.0030; K, = non-significant regression). All litters showed a reduction of lipid (mean loss 90.5%), hydrosoluble (mean loss, 54.2%), hemicellulose plus cellulose (mean loss, 40.6%) content and a relative increase of lignin content (mean gain, 34.4%). Among indicators of litter quality (C-to-N ratio, %N, %lignin, lignin-to-N ratio, HLQ), only some of them were correlated with litter decay. The best relationships were established between the decomposition rates (K,) and parameters integrating lignin contents (I = 0.997; n = 3; P < 0.01). The decomposition of l-y old litters fitted well with most of these parameters (0.999 < I < 0.997; n = 3; P < 0.01) in contrast to newly senescent litters
Keywords: Cellulose; decomposition; hemicellulose; leaf litter; Lignin; litter quality (voyant); mass loss; mineralization

The dense indumentum with its polyphenol content may replace the protective role of the epidermis in some young xeromorphic leaves - Karabourniotis, George; Fasseas, Costas (Canadian Journal of Botany, 1996)
The bright, yellow-green, ammonia-induced fluorescence of polyphenol compounds contained in the nonglandular hairs and within the epidermis of Olea europaea and Quercus ilex leaves was age dependent. Epifluorescence microscopic examination of transverse sections of leaves from both species showed that abaxial and adaxial epidermal layers emitted the characteristic green-yellow bright fluorescence only in late developmental stages, when a considerable decrease of the trichome density had already occurred. At earlier developmental stages, only the dense and thick trichome layer emitted the bright green-yellow fluorescence. In addition, the trichomes of young leaves of Olea and Quercus resembled the glandular ones of other species morphologically and possibly functionally. These findings suggest that the protective role of the trichome against ultraviolet-B radiation damage and (or) other environmental factors is particularly significant during the early stages of leaf development and may be less important at later stages, when the protective role is taken over by the epidermis. Keywords: leaf hairs, phenolics, UV-B radiation damage, leaf development, Olea europaea L., Quercus ilex L.
doi: 10.1139/b96-043doi: 10.1139/b96-043The following values have no corresponding Zotero field: publisher: NRC Research Press
Keywords: leaf development; leaf hairs; Olea europaea L.; phenolics; Quercus ilex L.; UV-B radiation damage

The dense indumentum with its polyphenol content may replace the protective role of the epidermis in some young xeromorphic leaves - Karabourniotis, George; Fasseas, Costas (Canadian Journal of Botany, 1996)
The bright, yellow-green, ammonia-induced fluorescence of polyphenol compounds contained in the nonglandular hairs and within the epidermis of Olea europaea and Quercus ilex leaves was age dependent. Epifluorescence microscopic examination of transverse sections of leaves from both species showed that abaxial and adaxial epidermal layers emitted the characteristic green-yellow bright fluorescence only in late developmental stages, when a considerable decrease of the trichome density had already occurred. At earlier developmental stages, only the dense and thick trichome layer emitted the bright green-yellow fluorescence. In addition, the trichomes of young leaves of Olea and Quercus resembled the glandular ones of other species morphologically and possibly functionally. These findings suggest that the protective role of the trichome against ultraviolet-B radiation damage and (or) other environmental factors is particularly significant during the early stages of leaf development and may be less important at later stages, when the protective role is taken over by the epidermis. Keywords: leaf hairs, phenolics, UV-B radiation damage, leaf development, Olea europaea L., Quercus ilex L.
doi: 10.1139/b96-043
Keywords: leaf development; leaf hairs; Olea europaea L.; phenolics; Quercus ilex L.; UV-B radiation damage

DETERMINACIÓN DE LOS RECURSOS ENERGÉTICOS QUE CUBREN LAS NECESIDADES ALIMENTICIAS EN SISTEMAS DE DEHESA1 DETERMINATION - SÁNCHEZ, E; Gaída, M F P; V&ga, A R L; Diaz, F J M (Archivos de Zootecnia, 1996)
Dehesas are farming systems that covers with their own resources agreat deal of cattle food needs. However. the use and contribution of these resources haven"t a uniform distribution between the diferent stock species. This paper deals with an analytical case study of characteristic dehesas of SW Badajoz (Spain), where the factors that influence the use of grazing resources have been determinated. The analyzed dehesas cover up to 73 p.100 of food needs for ruminants, but only 47 p.100 for Iberian pig. The knowledge of food energetic flows is a solid starting point to analyze the management and the sustainable use of dehesa resources.
Keywords: energetic analysis; Extensive systems; grazing resources; Shepherding

Different sources of reduced carbon contribute to form three classes of terpenoid emitted by Quercus ilex L leaves - Loreto, F; Ciccioli, P; Brancaleoni, E; Cecinato, A; Frattoni, M; Sharkey, T D (PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1996)
Quercus ilex L. leaves emit terpenes but do not have specialized structures for terpene storage. We exploited this unique feature to investigate terpene biosynthesis in intact leaves of Q. ilex. Light induction allowed us to distinguish three classes of terpenes: (i) a rapidly induced class including alpha-pinene; (ii) a more slowly induced class, including cis-beta-ocimene; and (iii) the most slowly induced class, including 3-methyl-3-buten-1-ol. Using C-13, we found that alpha-pinene and cis-beta-ocimene were labeled quickly and almost completely while there was a delay before label appeared in linalool and 3-methyl-3-buten-1-ol. The acetyl group of 3-methyl-3-buten-1-yl acetate was labeled quickly but label was limited to 20% of the moiety. It is suggested that the ocimene class of monoterpenes is made from one or more terpenes of the alpha-pinene class and that both classes are made entirely from reduced carbon pools inside the chloroplasts. Linalool and 3-methyl-3-buten-1-ol are made from a different pool of reduced carbon, possibly in nonphotosynthetic plastids. The acetyl group of the 3-methyl-3-buten-1-yl acetate is derived mostly from carbon that does not participate in photosynthetic reactions. Low humidity and prolonged exposure to light favored ocimenes emission and induced linalool emission. This may indicate conversion between terpene classes.
APS
Keywords: acetyl group labelling; alpha-pinene; light induction; monotherpenes; Quercus ilex L.; terpenes biosynthesis

Diurnal changes in photoprotective mechanisms in leaves of cork oak (Quercus suber) during summer - Faria, T; Garcia-Plazaola, J I; Abadía, A; Cerasoli, S; Pereira, J S; Chaves, M M (Tree Physiology, 1996)
Daily variations in photoprotective mechanisms were studied in sun and shade leaves of 40-year-old cork oak (Quercus suber L.) trees during early summer in Portugal. Although trees were not severely water stressed because predawn leaf water potentials remained high, photosynthesis and stomatal conductance decreased at midday. The midday depression in gas exchange was not reversed by short-term exposure to “optimal” conditions of temperature, light and vapor pressure deficit. Chlorophyll a fluorescence, maximum photochemical yield of photosystem II and the quantum yield of noncyclic electron transport showed midday depressions, but recovered by the evening. Both short-term changes in the components of the xanthophyll cycle (reversible de-epoxidation of violaxanthin during the day) as well as long-term changes (higher xanthophyll content in sun compared with shade leaves) were detected and may play a role in the dissipation of excess energy at midday. Because the activities of enzymes of the antioxidant system, superoxide dismutase and ascorbate peroxidase, were high enough to cope with the increase in oxygen reactive species likely to arise under the stressful conditions of midday, we conclude that these enzymes may provide an additional mechanism for energy dissipation.
10.1093/treephys/16.1-2.115
Keywords: antioxidants; photoinhibition; photosynthesis; Stomatal conductance; xanthophylls

Diversity and structure of ant communities associated with oak, pine, eucalyptus and arable habitats in Portugal - Cammell, M E; Way, M J; Paiva, M R (Insectes Sociaux, 1996)
In central Portugal, 28 species of ants were found in oak, 25 in pine, 35 in eucalyptus and 12 in arable habitats, a total of 43 species. They include five numerically dominant species, the exotic Argentine ant. Linepithema (Iridomyrmex) humile and four native species, Crematogaster scutel- laris, Pheidole pallidula, Tapinoma nigerrimum and Tetramorium hispanicum. L. humile occurred in 34 % of sampled sites. When present, it was abundant in all three arboreal habitats, where it was associated with strikingly decreased ant species richness and equitability. Such diversity was greater in L. humile - colonised arable habitats, where the ant was much less abundant than in the arboreal habitats. Where L. humile was absent, C. scutellaris and P pallidula were usually co-dominants in oak and pine, and T. nigerrimum and T. hispanicum in the arable habitat, but all were absent or rare in eucalyptus. Ants were numerically least abundant in eucalyptus but, in the absence of L. humile, species richness was greater and the community more equitable than in the other habitats. L. humile - absent arable habitats supported the poorest and least equitable ant community.
Keywords: Ants; community ecology; diversity; Dominance; Linepithema humile; Portugal.

Diversity and structure of ant communities associated with oak, pine, eucalyptus and arable habitats in Portugal - Cammell, M. E.; Way, M. J.; Paiva, M. R. (Insectes Sociaux, 1996)
In central Portugal, 28 species of ants were found in oak, 25 in pine, 35 in eucalyptus and 12 in arable habitats, a total of 43 species. They include five numerically dominant species, the exotic Argentine ant. Linepithema (Iridomyrmex) humile and four native species, Crematogaster scutel- laris, Pheidole pallidula, Tapinoma nigerrimum and Tetramorium hispanicum. L. humile occurred in 34 % of sampled sites. When present, it was abundant in all three arboreal habitats, where it was associated with strikingly decreased ant species richness and equitability. Such diversity was greater in L. humile - colonised arable habitats, where the ant was much less abundant than in the arboreal habitats. Where L. humile was absent, C. scutellaris and P pallidula were usually co-dominants in oak and pine, and T. nigerrimum and T. hispanicum in the arable habitat, but all were absent or rare in eucalyptus. Ants were numerically least abundant in eucalyptus but, in the absence of L. humile, species richness was greater and the community more equitable than in the other habitats. L. humile - absent arable habitats supported the poorest and least equitable ant community.
Keywords: Ants; community ecology; diversity; Dominance; Linepithema humile; Portugal.

Drought and photosystem II activity in two Mediterranean oaks - Méthy, M; Damesin, C; Rambal, S (Ann. For. Sci., 1996)
The responses of photosystem II (PS II) to drought were analysed on two Mediterranean oak species, Quercus ilex and Q pubescens, using the chlorophyll fluorescence pulse-amplitude-modulation technique. The maximal PS II photochemical efficiency (Fv/Fm) of the evergreen Q ilex and the deciduous Q pubescens oaks was only affected when leaf predawn water potential was lower than -4 MPa. This value is rarely observed on mature trees growing in the field, but can be undergone by young seedlings during drought periods, hence confirming the stability of PS II. Whatever the irradiance, drought resulted, in both species, in lower values of PS II photochemical efficiency in a light-adapted state (ΔF/F m'), due to stomatal closure and/or a direct inhibition of the dark reactions of photosynthesis. Diurnal decreases of Fv/Fm of 30 min dark-adapted leaves were greater for lower predawn water potential; a recovery was observed in the late afternoon. The reversible decreases in the diurnal time-courses of maximal fluorescence led us to assume the onset of protective mechanisms from permanent photodamages in Q ilex and, to a lesser extent, in Q pubescens.
Keywords: fluorescence; photoinhibition; Photosystem II; Quercus; water stress

The ecology of an endemic and rare species with a fragmented distribution: Cyclamen balearlcum Willk in France - Debussche, M.; Grandjanny, M.; Debussche, G.; Affre, L. (ACTA BOTANICA GALLICA, 1996)
The ecology of rare species is largely unknown. Though informations on the ecology of these species, as well as on their biological traits and genetics, are necessary to achieve their conservation. Ecology of Cyclamen balearicum Willk. in France was studied by analysing a set of 40 phyto-ecological releves. This late successional species grows in France under a mediterranean climate, in shaded situations, in sites characterized by moderate to copious precipitations (650 to 1800 mm per year) and frosts occurring each year commonly (mean of the minima of the coldest month from - 0,7 degrees C to + 0,7 degrees C), steep relief and north aspect, stony calcareous soils with blocks, important cover of evergreen woody plants, small number of therophytes, very Low human impact. Quercus ilex L. and Buxus sempervirens L. are very often the dominant tree and shrub species In these sites. Two kinds of habitat were distinguished. They mainly differ on geomorphological features, vegetation height and floristic composition. Ecological patterns were discussed in relation with decisive factors such as shade, frost and drainage, and human impacts. The farm or rarity showed by the species in France was discussed according to the criteria proposed by Rabinowitz. As numerous endemic species with narrow distribution, Cyclamen balearicum Willk. has in France a restricted habitat, but where it grows it is sometimes abundant.
The following values have no corresponding Zotero field: pub-location: RUE J B CLEMENT, 92296 CHATENAY-MALABRY CEDEX, FRANCE publisher: SOC BOTANIQUE FRANCE
Keywords: cyclamen balearicum Willk; ecology; endemic species France; habitat specificity; Mediterranean Region; rare species

The ecology of an endemic and rare species with a fragmented distribution: Cyclamen balearlcum Willk in France - Debussche, M; Grandjanny, M; Debussche, G; Affre, L (ACTA BOTANICA GALLICA, 1996)
The ecology of rare species is largely unknown. Though informations on the ecology of these species, as well as on their biological traits and genetics, are necessary to achieve their conservation. Ecology of Cyclamen balearicum Willk. in France was studied by analysing a set of 40 phyto-ecological releves. This late successional species grows in France under a mediterranean climate, in shaded situations, in sites characterized by moderate to copious precipitations (650 to 1800 mm per year) and frosts occurring each year commonly (mean of the minima of the coldest month from - 0,7 degrees C to + 0,7 degrees C), steep relief and north aspect, stony calcareous soils with blocks, important cover of evergreen woody plants, small number of therophytes, very Low human impact. Quercus ilex L. and Buxus sempervirens L. are very often the dominant tree and shrub species In these sites. Two kinds of habitat were distinguished. They mainly differ on geomorphological features, vegetation height and floristic composition. Ecological patterns were discussed in relation with decisive factors such as shade, frost and drainage, and human impacts. The farm or rarity showed by the species in France was discussed according to the criteria proposed by Rabinowitz. As numerous endemic species with narrow distribution, Cyclamen balearicum Willk. has in France a restricted habitat, but where it grows it is sometimes abundant.
Keywords: cyclamen balearicum Willk; ecology; endemic species France; habitat specificity; Mediterranean Region; rare species

Effect of scale on surface runoff processes - Barbancho, A C; Schnabel, S; Bolinches, C (CADERNOS DO LABORATORIO XEOLOXICO DE LAXE 21, 1996)
In a small catchment under the so-called dehesa landuse system, the production of surface runoff is investigated at different scales. This includes experiments with simulated rainfall at micro-plots, event-based measurements of overland flow at 17 open plots and 1 closed plot, and discharge production of the catchment and subcatchment. The runoff coefficients of the considered scales form two groups, with low values for the catchment and sub-catchment and high values for the microplots and hillslope plots. The results show that large part of runoff produced at the slopes is infiltrated afterwards at colluvial sites and the valley floors. Furthermore, they indicate the importance of studying at various scales in order to understand the hydrological processes operating in catchments.
Keywords: ecosystem dehesa; scale; soil erosion; surface runoff

Effect of scale on surface runoff processes - Barbancho, A. C.; Schnabel, S.; Bolinches, C. (CADERNOS DO LABORATORIO XEOLOXICO DE LAXE 21, 1996)
In a small catchment under the so-called dehesa landuse system, the production of surface runoff is investigated at different scales. This includes experiments with simulated rainfall at micro-plots, event-based measurements of overland flow at 17 open plots and 1 closed plot, and discharge production of the catchment and subcatchment. The runoff coefficients of the considered scales form two groups, with low values for the catchment and sub-catchment and high values for the microplots and hillslope plots. The results show that large part of runoff produced at the slopes is infiltrated afterwards at colluvial sites and the valley floors. Furthermore, they indicate the importance of studying at various scales in order to understand the hydrological processes operating in catchments.
The following values have no corresponding Zotero field: periodical: CADERNOS DO LABORATORIO XEOLOXICO DE LAXE 21 pub-location: O CASTRO DE SAMOEDO, 15168 SADA, LA CORUNA, SPAIN
Keywords: ecosystem dehesa; scale; soil erosion; surface runoff

Effect of site quality and thinning management on the structure of holm oak forests in northeast Spain - Gracia, M; RETANA, J (Ann. For. Sci., 1996)
In the holm oak forests of NE Spain, the variability of thinning intensity, together with the great heterogeneity of site quality, due to the rough topography of the region, gives rise to important structural differences among stands. In this paper, we analyze the effect of site quality and thinning management on the structural heterogeneity of holm oak stands at the end of the cutting cycle in different areas of the Montseny and Les Guilleries massifs (NE Spain). These two factors influence the main structural variables of the stands in various ways. Height was used as an indicator of site quality, because it was relatively unaffected by thinning management, while density and total number of stems per stool were strongly affected. Mean tree diameter reflected the effect of both site quality and thinning. The type of forest management was found to be the most important factor determining forest structure. Site quality was a constraint of stand development, contributing in poor stands, to increased differences due to thinning management.
Keywords: Forest structure; Holm oak; Ouercus ilex; site quality; thinning

Effect of undergrowth-clearing on evergreen leaf litter decomposition and colonization by microarthropods - POINSOTBALAGUER, N (PEDOBIOLOGIA, 1996)
The effect of undergrowth-clearing has been studied for two years in a mediterranean Quercus ilex forest. The emphasis has been put on decomposition rate of Quercus ilex leaves placed in nylon bags and on microarthropod populations colonizing the litter bags. Undergrowth-clearing magnifies the characteristics of mediterranean climate but the differences of decomposition rate and microarthropod populations in cleared and uncleared sites are significantly different only in relation to local conditions. In the two situations, the rational and asymptotic models are those which fitted the decomposition rate the best. Seasonal variations of microarthropod populations in the four sites followed the response pattern of these generally observed in mediterranean regions. There was no correlation between litter mass loss and microarthropod numbers in bags. Data of this study were compared with those from nearby areas of Provence or mediterranean xerophilous ecosystems.
Keywords: evergreen leaf; litter decomposition; undergrowth-clearing

Effect of water stress on monoterpene emissions from young potted holm oak (Quercus ilex L.) trees - Bertin, N; Staudt, M (Oecologia, 1996)
We investigated the effects of a short period of water stress on monoterpene emissions from Quercus il- ex, a common oak species of the Mediterranean vegeta- tion and a strong emitter of monoterpenes. The experi- ment was carried out on two young saplings with a branch enclosure system under semi-controlled condi- tions. Under unstressed conditions, small qualitative (cis- [3-ocimene, trans-~3-ocimene, [3-caryophyllene and 1,8- cineol) and large quantitative (as much as 40% for the main compounds emitted) differences were observed be- tween the two apparently similar trees. Nevertheless these differences did not affect the short- and long-term responses to temperature and water stress. Daily courses of emissions and gas exchanges were similar before and after the stress. During the most severe stress, emissions were reduced by a factor of two orders of magnitude and the log-linear relationship between emissions and tem- perature no longer existed. Photosynthesis and transpira- tion rates decreased as soon as the soil started to dry, whereas monoterpene emissions slightly increased for few days and then dropped when the daily CO 2 balance approached zero. We concluded that under water stress monoterpene emissions were highly limited by monoter- pene synthesis resulting from a lack of carbon substrate and/or ATR After rewatering, both emissions and gas ex- changes recovered immediately, but to a level lower than the pre-stress level. These results have many implica- tions for monoterpene emission modelling in the Medi- terranean area, since the dry period generally extends from May to August. If our results are confirmed by field experiments, water stress could lead to a large overesti- mation of the emissions under summer conditions, when the algorithms based on light and temperature would give high emission rates.
Keywords: Holm oak; Mediterranean vegetation; monoterpene emission; Quercus ilex; water stress

Effects of elevated carbon dioxide on leaf gas exchange and growth of cork-oak (Quercus suber L) seedlings - Damesin, C; Galera, C; Rambal, S; Joffre, R (Ann. For. Sci., 1996)
Leaf gas exchange and growth were determined on cork-oak (Quercus suber L) seedlings which were grown from acorns for periods of up to 4 months in greenhouses at ambient (350 μmol mol-1) and at elevated (700 μmol mor-1) concentrations of carbon dioxide. In well-watered conditions, daily maximum photosynthesis (15 μmol m-2 s -1) and stomatal conductance (440 mmol m-2 s-1) of plants grown and measured at 700 μmol mol-1 CO2 did not differ from those of plants grown and measured at 350 μmol mol-1. In conditions of moderate drought, net CO2 assimilation was at least twice as great in elevated CO2, but stomatal conductance was unchanged. Elevated CO2 affected total biomass production, the average increase being 76 and 97% at 3 and 4 months, respectively. Shoot biomass, root biomass, stem height and total leaf area were increased by elevated CO2. Root and stem ramification were also enhanced by elevated CO2, but no change in root/shoot ratio was observed.
Keywords: Carbon dioxide; Growth; photosynthesis; Quercus suber; Stomatal conductance

Effects of fire frequency on plant communities and landscape pattern in the Massif des Aspres (southern France) - Trabaud, L; Galtié, J F (Landscape Ecology, 1996)
Fire frequency can affect pattern and diversity in plant communities and landscapes. We had the opportunity to study changes due to recurring wildfires on the same sites over a period of 50 years in the "Massif des Aspres" (southern France). The study was carried out in areas occupied by Quercus suber and Q. ilex series. A comparison of historical and cartographical documents (vegetation maps covering a 50 year interval and an accurate map of major wildfires during this period) allowed us to determine the changes occurring over time with or without fire action. Plant communities were grouped into three main vegetation types: forests, treed shrublands and shrublands. The passage of three successive wildfires on the same site led to a decrease in for- est areas and an increase in shrublands; however, shrublands were already present before the first fire of the period under consideration. Less frequent fire occurrence induced more complex heterogeneity and greater landscape diversity. In the study region as a whole, with or without fire action, a significant decrease in forest surfaces was recorded, whereas there was an increase of unforested communities such as treed shrublands and shrublands. In some parts of the Massif fires increased the homogeneity of the landscape, in other parts they created a greater heterogeneity and diversity of plant communities.
Keywords: aspres; fire; landscape diversity; Quercus ilex; Quercus suber; Southern France

El paisaje vegetal de Extremadura, España - Ladero, Miguel (Giornale botanico italiano, 1996)
Abstract The landscape vegetation of Extremadura, Spain. - The main goal of this work is to gain insight into the landscape of region of Extremadura, located in the suothwest quadrant of the Iberian Peninsula. Owing to ecological factors such as temperature, rainfall and soil types, the predominant landscape of the territory is formed by Mediterranean clymatophylous series, whose main emplacements vary a function of the bioclimatic floor. Thus, the mesomediterranean feactures the holm oak (Quercus rotundifolia) and the cork oak (Quercus suber); the supramediterranean, the oak (Quercus pyrenaica), and the oromediterranean, formations of genista (Cytisus oromediterraneus, Echinopartum barnadesii, Genista cinerea subsp. cinerascens).Edaphohygrophylous series are represented by stands of alder (Alnus glutinosa), ash (Fraxinus angustifolia), willow (Salix sp. pl.), box-leafed broom (Securinega tinctoria) and oleander (Nerium oleander). In order to complete our knowledge of this landscape, of special relevance is the single-stratum vegetation colonizing biotopes such as cliffs and gravel pits, wich serve as a refuge to most of the endemic vegetation of Extremadura. On the quartzite rocks crowning the Silurian series, one finds as permanent communities the heliophobic fissuricolous communities belonging to the association Asplenio billotii-Cheianthetum hispanicae the heliophylous association of Diantho lusitani-Jasionetum tomentosi and, at the base of rock formations and isolated bocks the saxicolous communities of Digitali thapsi-Dianthetum lusitani and Phagnalo saxatilis-Rumicetum indurati. These biotopes have an endemic arbustive vegetation definided by Adenocarpetum argyrophylli.
doi: 10.1080/11263509609439514
Keywords: Extremadura; Geosynphytosociology; Iberian peninsula (citation)

EMISSION OF MONOTERPENES AND ISOPRENE FROM A MEDITERRANEAN OAK SPECIES QUERCUS ILEX L. MEASURED WITHIN THE BEMA (BIOGENIC EMISSIONS IN THE MEDITERRANEAN AREA) PROJECT EMISSIONS IN THE M E D I T E - Kesselmeier, J; Fer, L S C H; Ciccioli, P; Brancaleoni, E; Cecinato, A; Frattoni, M; Foster, I P; Jacob, V; Denis, J; Fugit, J L; Dutaur, L; Torres, L; et al. (Atmospheric Environment, 1996)
We report on some results of our studies of monoterpene and isoprene emissions and the physiological activities of an oak species (Quercus ilex L.) under the Mediterranean climatic conditions found at Castel Porziano (Rome) in June 1993. The oak species Quercus ilex L. was found to emit mainly monoterpenes in high amounts. Isoprene emissions were negligible. Diel cycles of monoterpene emissions showed correlation with light and the diel behaviour of photosynthetic CO2 assimilation, transpiration and stomatal corductance. Temperature dependence seemed to be of minor importance.
Keywords: Biogenic emission; isoprene; light; Monoterpenes; non-methane hydrocarbons; oak; Plant physiology; VOC

Environmental control of CO2 assimilation rates and stomatal conductance in five oak species growing under field conditions in Greece - Radoglou, K (Ann. For. Sci., 1996)
The present study compared CO2 assimilation rate and stomatal conductance of five oak species from the beginning of May through November 1993 under similar natural conditions. Gas exchange, leaf characteristics and water status were measured on 30-year-old Quercus ilex, Q macrolepis, Q pedunculiflora, Q pubescens and Q trojana growing in experimental plots in northern Greece. The seasonal pattern of assimilation rates was similar for all study species but differences occurred between the species. After initial leaf expansion, all species rapidly developed high photosynthetic rates. In addition, assimilation rates were high in all species in May and November after rain events. No significant differences in stomatal conductance were observed among species during the growing season. The relationships between assimilation rate and stomatal conductance displayed variation in the slopes among species and months.
Keywords: assimilation rate; Drought; Quercus sp; Seasonality; Stomatal conductance

Evidence of the photosynthetic origin of monoterpenes emitted by Quercus ilex L leaves by C-13 labeling - Loreto, F; Ciccioli, P; Cecinato, A; Brancaleoni, E; Frattoni, M; Fabozzi, C; Tricoli, D (PLANT PHYSIOLOGY, 1996)
The carbon of the four main monoterpenes emitted by Quercus flex L. leaves was completely labeled with C-13 after a 20-min feeding with 99% (CO2)-C-13. This labeling time course is comparable with the labeling time course of isoprene, the terpenoid emitted by other Quercus species and synthesized in leaf chloroplasts. It is also comparable with that of phosphoglyceric acid. Our experiment therefore provides evidence that monoterpenes emitted by Q. ilex are formed from photosynthesis intermediates and may share the same synthetic pathway with isoprene. By analyzing the rate and the distribution of labeling in the different fragments, we looked for evidence of differential carbon labeling in the alpha-pinene emitted. However, the labeling pattern was quite uniform in the different fragments, suggesting that the carbon skeleton of the emitted monoterpenes comes from a unique carbon source.
APS
Keywords: alpha-pinene; C-13 labeling; Emissions; isoprene; Monoterpenes; Quercus flex L.; Quercus ilex

Factors affecting yield of Tuber melanosporum in a Quercus ilex plantation in southern France - Shaw, P.J.a.; Lankey, K; Jourdan, A (Mycological Research, 1996)
Yields of Tuber nielanosporurn fruit bodies from a commercial truffle plantation are examined in relation to time, soil conditions and basal diameter of host tree. Fruiting started 10 yr after planting, and the number of trees producing truffles increased steadily for the following 8 yr. The best predictor of truffle production was tree basal diameter.
Keywords: host tree (PG); soil conditions; Tuber melanosporum; yield

Forage production and small ruminant grazing responses in Mediterranean shrublands as influenced by the reduction of shrub cover - Papachristou, T G; Platis, P D; PAPANASTASIS, V P (Agroforestry systems, 1996)
Reduction of shrub cover in Mediterranean shrublands is considered as a method of optimising forage and animal production. In this study, forage production in grazed and protected plots and grazing responses of small ruminants in cleared (25% shrub cover), slashed (34'7o shrub cover) and not treated (control, 55% shrub cover) kermes oak (Quercus coccifera L.) shrublands were compared during the spring seasons of 1992, 1993 and 1994. The alterations in shrub density were done in October 1991 and pastures remained ungrazed until spring of 1992. Clearing and slashing of shrub vegetation resulted in higher amounts of available herbaceous forage and useable browse. At the end of the growing season, averaged across years, herbaceous biomass was generally two to three times higher in the treated shrub- lands than in the control; also, browse biomass was slightly less (1,078 vs 1,533 kg/ha) but easily accessible because of the open structure and the lower height of the sprouting shrubs. There were generally no grazing response differences between the cleared and slashed pastures. However, grazing animals (sheep and goats) had a higher bite rate (bites/rain; P ~< 0.05) in the treated pastures than in the control. Levels of crude protein in the forage selected by animals were higher (P ~< 0.05) in the treated pastures than in the control. Animals in the improved pastures maintained diets that were significantly more digestible (53.5%) than those in the control pasture (48.5'7o). Neutral detergent fibre and lignin contents of animal diets were similar in the improved pastures but lower (P <~ 0.05) than those of the control. It is concluded that removing of woody vegetation in Mediterranean shrublands results in increased forage production (available herbage and useable browse) and improved forage quality and availability for small ruminants.
Keywords: Goats; greece; herbs; improvement; Sheep

Fungal endophytes in leaves, twigs and bark of Quercus ilex from Central Spain - Collado, J; Platas, G; Pelaez, F (NOVA HEDWIGIA, 1996)
Fungal endophytes were isolated from leaves, twigs and bark discs of the main stem of 16 individuals of Quercus ilex at two sites in the forests of El Pardo, Madrid, central Spain. From 512 segments of each sample type, 1084 fungal isolates were obtained, distributed among 98 species of filamentous fungi, yielding about 21 species/tree. Four isolation media were tested, which showed different behaviour depending on the type of sample. The use of fungitoxic compounds, such as benomyl or cycloheximide, resulted in a decrease in the number of isolates and species recovered, especially from leaves. Most of the dominant fungal species were not isolated from the four media indistinctly, but were preferentially recovered from one of the media. Twigs exhibited a higher degree of fungal infection than bark discs and leaves. The mycota isolated from bark and twigs were more similar to each other than to the fungal populations recovered from leaves. The frequency of isolation of most of the dominant fungal species depended significantly upon the sample type. A Phoma sp. was the only taxon similarly distributed among the three sample types. The height from which the bark discs were removed also influenced the population recovered. Both sampling sites were similar with respect to the number of species recovered from twigs and bark discs, but differed in the number of species from leaves. As in other plant and non-plant fungal communities, the population recovered from Q. ilex was characterized by a few species which accounted for most of the isolates, and a much larger number of species present with low frequencies. Five species (Nodulisporium sp., Acremonium strictum and three Phoma-like coelomycetes) represented more than 50% of the whole isolates. Coelomycetous anamorphs of ascomycetes bearing small, hyaline ameroconidia, were the most abundant group of fungi, whereas teleomorphs were rarely seen.
Keywords: endophytes; isolation; microbial diversity; Quercus ilex

Fungal endophytes in leaves, twigs and bark of Quercus ilex from Central Spain - Collado, J.; Platas, G.; Pelaez, F. (NOVA HEDWIGIA, 1996)
Fungal endophytes were isolated from leaves, twigs and bark discs of the main stem of 16 individuals of Quercus ilex at two sites in the forests of El Pardo, Madrid, central Spain. From 512 segments of each sample type, 1084 fungal isolates were obtained, distributed among 98 species of filamentous fungi, yielding about 21 species/tree. Four isolation media were tested, which showed different behaviour depending on the type of sample. The use of fungitoxic compounds, such as benomyl or cycloheximide, resulted in a decrease in the number of isolates and species recovered, especially from leaves. Most of the dominant fungal species were not isolated from the four media indistinctly, but were preferentially recovered from one of the media. Twigs exhibited a higher degree of fungal infection than bark discs and leaves. The mycota isolated from bark and twigs were more similar to each other than to the fungal populations recovered from leaves. The frequency of isolation of most of the dominant fungal species depended significantly upon the sample type. A Phoma sp. was the only taxon similarly distributed among the three sample types. The height from which the bark discs were removed also influenced the population recovered. Both sampling sites were similar with respect to the number of species recovered from twigs and bark discs, but differed in the number of species from leaves. As in other plant and non-plant fungal communities, the population recovered from Q. ilex was characterized by a few species which accounted for most of the isolates, and a much larger number of species present with low frequencies. Five species (Nodulisporium sp., Acremonium strictum and three Phoma-like coelomycetes) represented more than 50% of the whole isolates. Coelomycetous anamorphs of ascomycetes bearing small, hyaline ameroconidia, were the most abundant group of fungi, whereas teleomorphs were rarely seen.
The following values have no corresponding Zotero field: pub-location: JOHANNESSTR 3A, D-70176 STUTTGART, GERMANY publisher: GEBRUDER BORNTRAEGER
Keywords: endophytes; isolation; microbial diversity; Quercus ilex

FUNGI ASSOCIATED TO PLATYPUS CYLINDRUS FAB . ( COLEOPTERA : PLATYPODIDAE ) IN CORK OAK - Henriques, Joana; INÁCIO, MARIA D E LURDES; Sousa, Edmundo (Revista de Ciências Agrarias, 1996)
Platypus cylindrus is a pest that since the 80s of the last century has been considered a cork oak mortality agent in Portugal. It is an ambrosia beetle that establishes complex symbioses with fungi whose role in the insect-fungus-host interaction has not been completely clarified. In order to characterize P. cylindrus associated micoflora in Portugal, fungi were isolated from different beetle organs and from its galleries in cork oak trees. Fungi of the genera Acremonium, Aspergillus, Beauveria, Botrytis, Chaetomium, Fusarium, Geotrichum, Gliocladium, Nodulisporium, Paecilomyces, Penicillium, Raffaelea, Scytalidium, Trichoderma and of the order Mucorales were identified. An actinomycete of the genus Streptomyces was also identified. Some of these genera were related for the first time to this interaction. In the present work the isolated fungi are characterized and their contribution for beetle population establishment and tree weakness is discussed.
Keywords: Ambrosia beetle; decline; interaction; mycoflora; Quercus suber

GC−MS Study of Volatiles of Normal and Microbiologically Attacked Cork from Quercus suber L. - Rocha, Sílvia; Delgadillo, Ivonne; Ferrer Correia, A J (Journal of Agricultural and Food Chemistry, 1996)
The volatile compounds of cork were studied by gas chromatography and combined gas chromatography?high-resolution mass spectrometry using simultaneous distillation?extraction to prepare the samples. To assess the origin of the volatiles, three different types of samples were analyzed:? ?normal?, attacked by Armillaria mellea, and infested by molds. The study of the volatiles of these different types of corks allowed the identification of the chemical modifications which may occur in cork polymers. The cork attacked by A. mellea showed higher amounts of phenols, vanillin, benzaldehyde, benzyl alcohol, and chlorinated compounds than normal cork; this may indicate lignin degradation. The cork infested by molds contained higher levels of 3-methyl-1-butanol, 1-octen-3-ol, 1-octanol, 2-methylisoborneol, chlorinated compounds, and methyl ketones. These components resulting from microbial metabolism were also present in cork attacked by A. mellea. The use of cork attacked by A. mellea is not recommended in the manufacture of cork stoppers, since these types of cork have volatile compounds likely to cause off-flavors in wine. For the same reason it is important to reduce the likelihood of mold development during the standing period. Keywords: ?Normal? cork; Armillaria mellea; molds; volatile components; musty and moldy odors
doi: 10.1021/jf9500400
Keywords: Armillaria mellea; molds; musty and moldy odors; volatile components; “Normal” cork

GC−MS Study of Volatiles of Normal and Microbiologically Attacked Cork from Quercus suber L. - Rocha, Sílvia; Delgadillo, Ivonne; Ferrer Correia, A. J. (Journal of Agricultural and Food Chemistry, 1996)
The volatile compounds of cork were studied by gas chromatography and combined gas chromatography?high-resolution mass spectrometry using simultaneous distillation?extraction to prepare the samples. To assess the origin of the volatiles, three different types of samples were analyzed:? ?normal?, attacked by Armillaria mellea, and infested by molds. The study of the volatiles of these different types of corks allowed the identification of the chemical modifications which may occur in cork polymers. The cork attacked by A. mellea showed higher amounts of phenols, vanillin, benzaldehyde, benzyl alcohol, and chlorinated compounds than normal cork; this may indicate lignin degradation. The cork infested by molds contained higher levels of 3-methyl-1-butanol, 1-octen-3-ol, 1-octanol, 2-methylisoborneol, chlorinated compounds, and methyl ketones. These components resulting from microbial metabolism were also present in cork attacked by A. mellea. The use of cork attacked by A. mellea is not recommended in the manufacture of cork stoppers, since these types of cork have volatile compounds likely to cause off-flavors in wine. For the same reason it is important to reduce the likelihood of mold development during the standing period. Keywords: ?Normal? cork; Armillaria mellea; molds; volatile components; musty and moldy odors
doi: 10.1021/jf9500400doi: 10.1021/jf9500400The following values have no corresponding Zotero field: publisher: American Chemical Society
Keywords: Armillaria mellea; molds; musty and moldy odors; volatile components; “Normal” cork

Growth at elevated CO2 leads to down-regulation of photosynthesis and altered response to high temperature in Quercus suber L. seedlings - Faria, T; Wilkins, D; Besford, R T; Vaz, M; Pereira, J S; Chaves, M M (Journal of Experimental Botany, 1996)
The effects of growth at elevated CO2 on the response to high temperatures in terms of carbon assimilation (net photosynthesis, stomatal conductance, amount and activity of Rubisco, and concentrations of total soluble sugars and starch) and of photochemistry (for example, the efficiency of excitation energy captured by open photosystem II reaction centres) were studied in cork oak (Quercus suber L.). Plants grown in elevated CO2 (700 ppm) showed a down-regulation of photosynthesis and had lower amounts and activity of Rubisco than plants grown at ambient CO2 (350 ppm), after 14 months in the greenhouse. At that time plants were subjected to a heat-shock treatment (4 h at 45°C in a chamber with 80% relative humidity and 800–1000 µmol m−2 s−1 photon flux density). Growth in a CO2-enriched atmosphere seems to protect cork oak leaves from the short-term effects of high temperature. Elevated CO2 plants had positive net carbon uptake rates during the heat shock treatment whereas plants grown at ambient CO2 showed negative rates. Moreover, recovery was faster in high CO2-grown plants which, after 30 min at 25°C, exhibited higher net carbon uptake rates and lower decreases in photosynthetic capacity (Amax as well as in the efficiency of excitation energy captured by open photosystem II reaction centres (FvJFm than plants grown at ambient CO2. The stomata of elevated CO2 plants were also less responsive when exposed to high temperature.
10.1093/jxb/47.11.1755
Keywords: acclimation; Elevated CO2; photo- synthesis; Quercus suber L.; Temperature

Growth at elevated CO2 leads to down-regulation of photosynthesis and altered response to high temperature in Quercus suber L. seedlings - FARIA, T.; Wilkins, D.; Besford, R. T.; Vaz, M.; Pereira, J. S.; Chaves, M. M. (Journal of Experimental Botany, 1996)
The effects of growth at elevated CO2 on the response to high temperatures in terms of carbon assimilation (net photosynthesis, stomatal conductance, amount and activity of Rubisco, and concentrations of total soluble sugars and starch) and of photochemistry (for example, the efficiency of excitation energy captured by open photosystem II reaction centres) were studied in cork oak (Quercus suber L.). Plants grown in elevated CO2 (700 ppm) showed a down-regulation of photosynthesis and had lower amounts and activity of Rubisco than plants grown at ambient CO2 (350 ppm), after 14 months in the greenhouse. At that time plants were subjected to a heat-shock treatment (4 h at 45°C in a chamber with 80% relative humidity and 800–1000 µmol m−2 s−1 photon flux density). Growth in a CO2-enriched atmosphere seems to protect cork oak leaves from the short-term effects of high temperature. Elevated CO2 plants had positive net carbon uptake rates during the heat shock treatment whereas plants grown at ambient CO2 showed negative rates. Moreover, recovery was faster in high CO2-grown plants which, after 30 min at 25°C, exhibited higher net carbon uptake rates and lower decreases in photosynthetic capacity (Amax as well as in the efficiency of excitation energy captured by open photosystem II reaction centres (FvJFm than plants grown at ambient CO2. The stomata of elevated CO2 plants were also less responsive when exposed to high temperature.
10.1093/jxb/47.11.175510.1093/jxb/47.11.1755
Keywords: acclimation; Elevated CO2; photo- synthesis; Quercus suber L.; Temperature

Habitat selection patterns of common cranes Grus grus wintering in holm oak Quercus ilex dehesas of central Spain: Effects of human management - Diaz, M; González, E (Biological Conservation, 1996)
Most of the western European population of common cranes Grus grus spends the winter in Iberian wooded dehesas, a kind of wood-pasture composed of grasslands, cereal croplands and Mediterranean scrub, densely inter- spersed with holm oak trees Quercus ilex in a savanna- like landscape. Three main types of wooded dehesas can be distinguished according to management." grazed dehesas, shrubby dehesas with occasional grazing, and cultivated dehesas without livestock. Cranes depend largely on acorns during winter and mainly select dehesas cultivated with cereals where acorn abundance is not reduced by livestock. Apparent positive effects of livestock on earth- worm abundance, the main alternative food source for cranes, does not compensate for acorn depletion. Thus, any increase in livestock grazing pressure would have a strong impact on European crane populations during their wintering in Spain.
Keywords: common agricultural policy; Cranes; livestock management; winter feeding

Habitat selection patterns of common cranes Grus grus wintering in holm oak Quercus ilex dehesas of central Spain: Effects of human management - Díaz, M.; González, E. (Biological Conservation, 1996)
Most of the western European population of common cranes Grus grus spends the winter in Iberian wooded dehesas, a kind of wood-pasture composed of grasslands, cereal croplands and Mediterranean scrub, densely inter- spersed with holm oak trees Quercus ilex in a savanna- like landscape. Three main types of wooded dehesas can be distinguished according to management." grazed dehesas, shrubby dehesas with occasional grazing, and cultivated dehesas without livestock. Cranes depend largely on acorns during winter and mainly select dehesas cultivated with cereals where acorn abundance is not reduced by livestock. Apparent positive effects of livestock on earth- worm abundance, the main alternative food source for cranes, does not compensate for acorn depletion. Thus, any increase in livestock grazing pressure would have a strong impact on European crane populations during their wintering in Spain.
Keywords: common agricultural policy; Cranes; livestock management; winter feeding

High - pressure extraction of cork with CO2 and 1,4-dioxane - Miranda, Ana M; Reis Machado, Ana S; Pereira, Helena; Nunes da Ponte, Manuel (High Pressure Chemical Engineering Proceedings of the 3rd International Symposium on High Pressure Chemical Engineering, 1996)
The extraction of cork from cork-oak (Quercus suber L.) by high-pressure dioxane and supercritical CO2 mixtures was studied at 170 bar and in the temperature range of 160°C - 180°C. Suberin is preferably extracted, but extraction percentages were lower than 46%. Lignin extraction percentages are lower than 11%. Extraction selectivity did not change significantly with extracting fluid composition. The results so far obtained support the idea of the existence of an extensive polymeric system across the cell wall and the concept of a close interaction of suberin and lignin, which hinders lignin depolymerization and solubilization in the high-pressure fluid. Fourier transform infrared spectra of cork, extraction residues and extracts are also presented.
Keywords: 1; 4-Dioxane; Cork; high-pressure extraction; suberin; supercritical CO2

Hymenoptera reared from Plagiotrochus suberi (Hymenoptera: Cynipidae) galls in California - Zuparko, R L (Pan-Pacific Entomologist, 1996)
Nine species of Hymenoptera were reared from stem galls induced by Plagiotrochus suberi Weld on Quercus suber L. in Albany, California. The most numerous species reared was P. suberi, but Euderus crawfordi Peck was the most common parasitoid reared. Other species reared were: Aprostocetus pattersonae (Fullaway), A. sp. nr. verrucarii (Balduf), Acaenacis taciti (Girault), Sycophila wiltzae(Balduf), Sycophila sp, possibly foliatae (Ashmead), Brasema sp. and Ceraphron sp. The rearings of all parasitoids (except E. crawfordi and S. wiltzae) constitute new host records. All described parasitoid species are native to North America and represent new associations with the introduced P. suberi.
Keywords: associations; Euderus crawfordi; Insecta; new; Parasitoids; Plagiotrochus suberi; Pragas e doenças do sobreiro - Plagiotrochus suber; Quercus suber

Improvement of the Volatile Components of Cork from Quercus suber L. by an Autoclaving Procedure - Rocha, Sílvia; Delgadillo, Ivonne; Ferrer Correia, A J (Journal of Agricultural and Food Chemistry, 1996)
The volatiles of cork slabs submitted to a novel industrial treatment, autoclaving, were compared with the volatiles of the untreated slabs to establish the usefulness of this treatment as a cleanup procedure. The condensed steams corresponding to the first and a second autoclaving process were also analyzed. The volatile compounds of cork and of autoclaved condensed steam were extracted by simultaneous distillation?extraction and analyzed by gas chromatography and combined gas chromatography?high-resolution mass spectrometry. Cork slabs treated with steam under pressure showed smaller amounts of the volatile components with musty, moldy, and related odors, such as 3-methyl-1-butanol, 1-octanol, and guaiacol and other mold metabolites. The condensed steam contained compounds corresponding to those extracted from the cork. The autoclaving process has potential for industrial use to clean the cork and to reduce volatiles of microbial origin in cork samples. Keywords: Quercus suber L.; volatiles; autoclaving process; condensed steam; musty and moldy odors
doi: 10.1021/jf950041s
Keywords: autoclaving process; condensed steam; musty and moldy odors; Quercus suber L.; volatiles

Incidence des caractéristiques structurales du sous-sol sur l'entrée en production de Tuber melanosporum et d'autres champignons mycorhiziens - Callot, G; Jaillard, B; Braye, J P; Jalade, M (Agronomie, 1996)
Effect of structural characteristics of subsoil on the fruiting of Tuber melanosporum and other mycorrhizal fungi. The collection sites for ascocarps of Tuber melanosporum Vitt were noted over four consecutive years in a truffle bed of live oaks (Quercus ilex) mycorrhized by T melanosporum. The mycorrhizas of Tuber and other fungi were checked 11 years after planting. At the same time, a detailed soil survey made it possible to distinguish different soil units within the truffle bed. Cartographic analysis of the data set showed that the mycorrhizal status and the location of the fungus collection sites were related to the structural characteristics of the subsoil. The presence of a slightly permeable clay subsoil discourages fruiting in both epigeal and hypogeal fungi. Soils presenting a shallow calcareous crust discourage the growth of hypogeal Tuber-type fungi, but encourage that of epigeal fungi. T melanosporum grows best in soils with a very porous horizon developed in contact with the calcareous bedrock. This horizon (termed Bbio by the authors) is characterized by an intensive biological activity.
Keywords: autoecology; fungi; limestone; Mycorrhizas; subsoil; Tuber

Incidence des caractéristiques structurales du sous-sol sur l'entrée en production de Tuber melanosporum et d'autres champignons mycorhiziens - Callot, G.; Jaillard, B.; Braye, J. P.; Jalade, M. (Agronomie, 1996)
Effect of structural characteristics of subsoil on the fruiting of Tuber melanosporum and other mycorrhizal fungi. The collection sites for ascocarps of Tuber melanosporum Vitt were noted over four consecutive years in a truffle bed of live oaks (Quercus ilex) mycorrhized by T melanosporum. The mycorrhizas of Tuber and other fungi were checked 11 years after planting. At the same time, a detailed soil survey made it possible to distinguish different soil units within the truffle bed. Cartographic analysis of the data set showed that the mycorrhizal status and the location of the fungus collection sites were related to the structural characteristics of the subsoil. The presence of a slightly permeable clay subsoil discourages fruiting in both epigeal and hypogeal fungi. Soils presenting a shallow calcareous crust discourage the growth of hypogeal Tuber-type fungi, but encourage that of epigeal fungi. T melanosporum grows best in soils with a very porous horizon developed in contact with the calcareous bedrock. This horizon (termed Bbio by the authors) is characterized by an intensive biological activity.
Keywords: autoecology; fungi; limestone; Mycorrhizas; subsoil; Tuber

Influence of environmental factors and air composition on the emission of alpha-pinene from Quercus ilex leaves - Loreto, F; Ciccioli, P; Cecinato, A; Brancaleoni, E; Frattoni, M; Tricoli, D (PLANT PHYSIOLOGY, 1996)
We studied the emission of alpha-pinene from Quercos ilex leaves. Only the abaxial side of the hypostomatous Q. ilex leaf emits alpha-pinene. Light induced photosynthesis and alpha-pinene emission. However, the response of photosynthesis to dark-to-light transitions was faster than that of alpha-pinene, suggesting that ATP controls the emission. The emission was higher at 30 than at 20 degrees C, whereas photosynthesis did not change. Therefore, the relationship between photosynthesis and alpha-pinene emission does not always hold. When CO2 was removed from the air, transpiration was stimulated but photosynthesis and alpha-pinene emission were inhibited. alpha-Pinene inhibition was more rapid under low O-2. When CO2 in the air was increased, photosynthesis was stimulated and transpiration was reduced, but alpha-pinene emission was unaffected. Therefore, the emission depends on the availability of photosynthetic carbon, is not saturated at ambient CO2, and is not dependent on stomatal opening. The pattern of alpha-pinene emission from Q. ilex is different from that of plants having specialized structures for storage and emission of terpenes. We suggest that alpha-pinene emitted by Q. ilex leaves is synthesized in the chloroplasts and shares the same biochemical pathway with isoprene emitted by isoprene-emitting oak species.
APS
Keywords: alpha-pinene; photosynthesis; Quercus ilex

Influence of fire and tree-fell on physiological parameters in Quercus ilex resprouts - Fleck, I.; Grau, D.; Sanjose, M.; Vidal, D. (Ann. For. Sci., 1996)
Variations in the physiology of two kinds of resprout (originated after fire and after tree-fell) of Quercus ilex were analyzed under field conditions and compared with respect to the original, undisturbed vegetation, located within a Mediterranean watershed (northeast Spain). Resprouting vegetation of Quercus ilex after fire or after tree-fell showed, during the next growing seasons, enhanced photosynthesis, leaf conductance and Rubisco activity with respect to the original vegetation, especially under high temperature, irradiance and vapor pressure deficit (VPD). The lack of differences in nutrient (N,C,P,K and Ca) and soluble carbohydrate concentrations in leaves of resprouts originated after fire or after tree-fell indicates the independence of nutrients released by the action of fire and the contribution of underground organs. Differences in leaf mass per area (LMA) were due to increased thickness in resprouts whereas density was the same. N investment in chlorophylls or Rubisco was not different in control or either kind of resprout. The increased amount of carotenoids in resprouts contributed to providing protection from photoinhibitory processes
Keywords: fire; Gas exchange; Nutrients; photosynthetic pigments; Quercus ilex; tree-fell

Influence of fire and tree-fell on physiological parameters in Quercus ilex resprouts - Fleck, I; Grau, D; Sanjosé, M; Vidal, D (Ann. For. Sci., 1996)
Variations in the physiology of two kinds of resprout (originated after fire and after tree-fell) of Quercus ilex were analyzed under field conditions and compared with respect to the original, undisturbed vegetation, located within a Mediterranean watershed (northeast Spain). Resprouting vegetation of Quercus ilex after fire or after tree-fell showed, during the next growing seasons, enhanced photosynthesis, leaf conductance and Rubisco activity with respect to the original vegetation, especially under high temperature, irradiance and vapor pressure deficit (VPD). The lack of differences in nutrient (N,C,P,K and Ca) and soluble carbohydrate concentrations in leaves of resprouts originated after fire or after tree-fell indicates the independence of nutrients released by the action of fire and the contribution of underground organs. Differences in leaf mass per area (LMA) were due to increased thickness in resprouts whereas density was the same. N investment in chlorophylls or Rubisco was not different in control or either kind of resprout. The increased amount of carotenoids in resprouts contributed to providing protection from photoinhibitory processes
Keywords: fire; Gas exchange; Nutrients; photosynthetic pigments; Quercus ilex; tree-fell

Influence of the wetting properties of polymeric adhesives on the mechanical behaviour of cork agglomerates - Teixeira, M. J.; Fernandes, A. C.; Saramago, B.; ROSA, M. E.; BORDADO, J. C. (JOURNAL OF ADHESION SCIENCE AND TECHNOLOGY, 1996)
A series of adhesives, polyurethane prepolymers with alkane chains of different functionalities, were used in the production of cork agglomerates. The polymeric structure varied from long, linear chains in adhesive M1 (14% isocyanate groups) to short, branched chains in adhesive M4 (30% isocyanate groups). The wetting properties of the adhesives were studied through surface tension and contact angle measurements of the polymeric liquids deposited on cork substrates. The mechanical behaviour of the cork agglomerates was studied through compression and three-point bending tests, and the agglomerate structure was analysed by scanning electron microscopy (SEM). The relationship between the structural and wetting characteristics of the adhesives and the mechanical properties of the agglomerates was investigated. The experimental results indicate that it is the work of adhesion for the adhesive/cork system, and not only the contact angle, which determines the mechanical resistance of the cork agglomerate.
The following values have no corresponding Zotero field: pub-location: PLANTIJNSTRAAT 2, P O BOX 9000, 2300 PA LEIDEN, NETHERLANDS publisher: BRILL ACADEMIC PUBLISHERS
Keywords: adhesives; cork agglometares; mechanical properties; WETTING

Influence of the wetting properties of polymeric adhesives on the mechanical behaviour of cork agglomerates - Teixeira, M J; Fernandes, A C; Saramago, B; Rosa, M E; Bordado, J C (JOURNAL OF ADHESION SCIENCE AND TECHNOLOGY, 1996)
A series of adhesives, polyurethane prepolymers with alkane chains of different functionalities, were used in the production of cork agglomerates. The polymeric structure varied from long, linear chains in adhesive M1 (14% isocyanate groups) to short, branched chains in adhesive M4 (30% isocyanate groups). The wetting properties of the adhesives were studied through surface tension and contact angle measurements of the polymeric liquids deposited on cork substrates. The mechanical behaviour of the cork agglomerates was studied through compression and three-point bending tests, and the agglomerate structure was analysed by scanning electron microscopy (SEM). The relationship between the structural and wetting characteristics of the adhesives and the mechanical properties of the agglomerates was investigated. The experimental results indicate that it is the work of adhesion for the adhesive/cork system, and not only the contact angle, which determines the mechanical resistance of the cork agglomerate.
Keywords: adhesives; cork agglometares; mechanical properties; WETTING

Influência do genótipo, idade da planta mãe e posição do explante inicial, na capacidade de multiplicação in vitro do sobreiro (Quercus suber L.) - Peixe, A.; Cavaleiro, C.; Mendes, A.; Gonçalves, J. C. (Simpósio de Propagação Vegetativa de Espécies Lenhosas, Castelo Branco, 18 a 20 de Abril de 1996, 1996)
O material utilizado foi recolhido em árvores adultas e em plantas provenientes da enxertia de árvores adultas sobre jovens plantas de origem seminal. Como explantes iniciais foram utilizados ramos do ano, tendo-se separado por grupos os explantes provenientes do gomo terminal e do primeiro, segundo e terceiro gomos axilares bem diferenciados. O meio de cultura utilizado foi o Woody Plant Medium (WPM) suplementado com 0,1 mgl-1 de BAP, 7gl-1 de Difco Bacto Agar e 20gl-1 de sacarose. Foram encontradas diferenças significativas entre os genótipos, tanto ao nível da idade da planta mãe como da posição do gomo utilizado. Os resultados obtidos com as plantas enxertadas, foram sempre significativamente superiores aos obtidos com as árvores adultas. Quanto à posição relativa do gomo, verifica-se que tanto ao nível do abrolhamento, como ao nível das taxas de multiplicação, no primeiro subcultivo, os melhores resultados foram obtidos quando se utilizaram os gomos terminais. Note-se no entanto que estas diferenças inicialmente significativas, se encontram já bastante atenuadas ao nível do segundo subcultivo. Outro aspecto com interesse e que mostra a dificuldade para multiplicar in vitro o sobreiro através de rebentação axilar utilizando genótipos adultos, é dado pela percentagem de explantes não evoluídos, que chega a atingir os 75%. As plantas enxertadas apresentaram um comportamento bastante melhor a todos os níveis, o que nos leva a pensar na provável ocorrência de um rejuvenescimento dos tecidos devido ao facto de a enxertia ter sido realizada sobre jovens plantas de semente.
The following values have no corresponding Zotero field: periodical: Simpósio de Propagação Vegetativa de Espécies Lenhosas, Castelo Branco, 18 a 20 de Abril de 1996 pub-location: Castelo Branco
Keywords: cultura in vitro; propagação; sobreiro

Influência do genótipo, idade da planta mãe e posição do explante inicial, na capacidade de multiplicação in vitro do sobreiro (Quercus suber L.) - Peixe, A; Cavaleiro, C; Mendes, A; Gonçalves, J C (Simpósio de Propagação Vegetativa de Espécies Lenhosas, Castelo Branco, 18 a 20 de Abril de 1996, 1996)
O material utilizado foi recolhido em árvores adultas e em plantas provenientes da enxertia de árvores adultas sobre jovens plantas de origem seminal. Como explantes iniciais foram utilizados ramos do ano, tendo-se separado por grupos os explantes provenientes do gomo terminal e do primeiro, segundo e terceiro gomos axilares bem diferenciados. O meio de cultura utilizado foi o Woody Plant Medium (WPM) suplementado com 0,1 mgl-1 de BAP, 7gl-1 de Difco Bacto Agar e 20gl-1 de sacarose. Foram encontradas diferenças significativas entre os genótipos, tanto ao nível da idade da planta mãe como da posição do gomo utilizado. Os resultados obtidos com as plantas enxertadas, foram sempre significativamente superiores aos obtidos com as árvores adultas. Quanto à posição relativa do gomo, verifica-se que tanto ao nível do abrolhamento, como ao nível das taxas de multiplicação, no primeiro subcultivo, os melhores resultados foram obtidos quando se utilizaram os gomos terminais. Note-se no entanto que estas diferenças inicialmente significativas, se encontram já bastante atenuadas ao nível do segundo subcultivo. Outro aspecto com interesse e que mostra a dificuldade para multiplicar in vitro o sobreiro através de rebentação axilar utilizando genótipos adultos, é dado pela percentagem de explantes não evoluídos, que chega a atingir os 75%. As plantas enxertadas apresentaram um comportamento bastante melhor a todos os níveis, o que nos leva a pensar na provável ocorrência de um rejuvenescimento dos tecidos devido ao facto de a enxertia ter sido realizada sobre jovens plantas de semente.
Keywords: cultura in vitro; propagação; sobreiro

Isolation and characterization of a lignin-like polymer of the cork of Quercus suber L. - Neto, C P; Cordeiro, N; Seca, A; Domingues, F; Gandini, A; Robert, D (HOLZFORSCHUNG, 1996)
A lignin-like polymer was successfully extracted from the cork of Quercus suber L. using an organosolv-based technique. This material was characterized by elemental analysis, functional group analysis, nitrobenzene oxidation followed by HPLC analysis of the oxidation products, FTIR and liquid C-13 NMR. The evidence thus obtained indicated that the extracted material was composed mainly of a lignin-like polymer covalently bound to residual aliphatic structures which are not present in common lignins and which have been assigned to suberin. The latter is likely to be attached to the oxygenated side chains of the phenolic polymer but bonding through the aromatic ring can also be envisaged. No residual carbohydrates were detected. The phenolic polymer, composed mainly of guaiacyl-type units and small amounts of syringyl-type units, had a low methoxy content and a high degree of condensation. This polymer showed the presence of a fraction containing C6Cn units with n < 3 or even n < 2.
Keywords: Cork; lignin-like polymer; Quercus Suber L; suberin

Isozyme variation in natural populations of cork-oak (Quercus suber L) - Population structure, diversity, differentiation and gene flow - ElenaRossello, J A; Cabrera, E (SILVAE GENETICA, 1996)
Genetic variation of cork-oak (Quercus suber L.) was investigated in 7 Mediterranean populations in Spain using 13 loci from 7 enzyme systems. Quercus suber was found to possess higher values of heterozygosity (H = 0.288 +/- 0.069), percent of polymorphic loci at the 99% criterion (P = 76.9%) and average number of alleles per locus (A = 2.46), than any other oak species. Interpopulation diversity was about 16.9% of the total diversity. The average estimated of Nm based on 10 loci is 2.57, and shows current or recent gene now among populations. Genetic identities among populations were moderate, ranging from I = 0.829 to I = 0.999, and a cluster analysis revealed no patterns related to geography. Our results revealed that the Q. suber populations studied share a common gene pool. The number of alleles and genotypes and the levels of genetic variability in the study populations, indicate that the Spanish populations are genetically rich. These high levels of genetic variability, coupled with the ecological and economic importance of the species make Q. suber a strong candidate for a gene conservation program.
Keywords: gene diversity; gene flow; genetic differentiation; genetic identities; isozymes; population structure; Quercus suber

Isozyme variation in natural populations of cork-oak (Quercus suber L) - Population structure, diversity, differentiation and gene flow - ElenaRossello, J. A.; Cabrera, E. (SILVAE GENETICA, 1996)
Genetic variation of cork-oak (Quercus suber L.) was investigated in 7 Mediterranean populations in Spain using 13 loci from 7 enzyme systems. Quercus suber was found to possess higher values of heterozygosity (H = 0.288 +/- 0.069), percent of polymorphic loci at the 99% criterion (P = 76.9%) and average number of alleles per locus (A = 2.46), than any other oak species. Interpopulation diversity was about 16.9% of the total diversity. The average estimated of Nm based on 10 loci is 2.57, and shows current or recent gene now among populations. Genetic identities among populations were moderate, ranging from I = 0.829 to I = 0.999, and a cluster analysis revealed no patterns related to geography. Our results revealed that the Q. suber populations studied share a common gene pool. The number of alleles and genotypes and the levels of genetic variability in the study populations, indicate that the Spanish populations are genetically rich. These high levels of genetic variability, coupled with the ecological and economic importance of the species make Q. suber a strong candidate for a gene conservation program.
The following values have no corresponding Zotero field: pub-location: FINKENHOFSTRASSE 21, W-6000 FRANKFURT, GERMANY publisher: SAUERLANDERS VERLAG
Keywords: gene diversity; gene flow; genetic differentiation; genetic identities; isozymes; population structure; Quercus suber

La gestion des taillis de chênes vert et pubescent dans les garrigues du Gard - Curt, Thomas (Ingénieries EAT, 1996)
Medium term management of ageing Holm Oak (Quercus ilex L.) and Downy Oak (Quercus pubescens Willd.) coppices in the Gard requires a thorough understanding of the natural environments and yields of the plantations. This paper puts forward a method for analysing the environment and plantation in order to assess the yield of the oak coppices. 118 small stands were studied in different types of coppices. In general, two environmental parameters determined the dominant height of the stand: geopedological conditions (rock, parent material and soil) and topoclimate which depends on the position of the plantation (orientation and topography). The growth height is affected by the structure and composi- tion of the plantation, together with the forestry and plant growth characteristics. Multivariate ana- lyses enabled 9 types and sub-types of sites to be distinguished with particular environmental con- ditions (soil and topoclimate). The type of site is closely correlated to the variation in the dominant height of the plantations. Growth classes are proposed for the Holm Oak (3 classes) and the Downy Oak (4 classes). These results should assist plantation management selection: the best coppices should possibly be allowed to develop as standards, plantations of average fertility should be treated as simple coppices, coppices with low growth rate should be allowed to grow on. 83
Keywords: Chêne pubescent; chêne vert; conditions geopedologiques (voyant); croissance en hauteur; Gard; Garrigue; peuplements; taillis

La gestion des taillis de chênes vert et pubescent dans les garrigues du Gard - Curt, Thomas (Ingénieries EAT, 1996)
Medium term management of ageing Holm Oak (Quercus ilex L.) and Downy Oak (Quercus pubescens Willd.) coppices in the Gard requires a thorough understanding of the natural environments and yields of the plantations. This paper puts forward a method for analysing the environment and plantation in order to assess the yield of the oak coppices. 118 small stands were studied in different types of coppices. In general, two environmental parameters determined the dominant height of the stand: geopedological conditions (rock, parent material and soil) and topoclimate which depends on the position of the plantation (orientation and topography). The growth height is affected by the structure and composi- tion of the plantation, together with the forestry and plant growth characteristics. Multivariate ana- lyses enabled 9 types and sub-types of sites to be distinguished with particular environmental con- ditions (soil and topoclimate). The type of site is closely correlated to the variation in the dominant height of the plantations. Growth classes are proposed for the Holm Oak (3 classes) and the Downy Oak (4 classes). These results should assist plantation management selection: the best coppices should possibly be allowed to develop as standards, plantations of average fertility should be treated as simple coppices, coppices with low growth rate should be allowed to grow on. 83
Keywords: Chêne pubescent; chêne vert; conditions geopedologiques (voyant); croissance en hauteur; Gard; Garrigue; peuplements; taillis

LAS BOÑIGAS DE VACA, EL ENCESPEDADO DE POA BULBOSA, Y LA DIVERSIDAD EN UN PASTIZAL DE DEHESA - Malo, J E Juan E; Suarez, F; Vaca, L A S Boñigas D E; Poa, E L Encespedado D E; Diversidad, Y L A; Un, E N; Dehesa, Pastizal D E (Pastos, 1996)
The interactions of cattle dung pats, the Poa bulbosa Turf and the number of species in a pasture is analyzed at a 10x10 cm scale, through a four-year monitoring of 50 dung pats. Dung pats elimínate the Poa bulbosa Turf, and its recovering takes more than four years. The rest of the species are also displaced by dung pats, but they colonize the gaps much faster. Thus, the number of species by sample is significantly smaller on dung pats the first year after deposition (5-4 vs. 10-8), not distinguishable the second and third years (9-2 vs. 10-0 and 9-3 vs. 8-0), and significantly higher the fourth year after depo- sition (13-8 vs. 10-7). These results seem to be associated to the competitive behaviour of Poa bulbosa. This species colonizes the gaps slowly, but it is able to displace other species from them. The effect of the process is relatively small for the whole pasture due to the small área covered by dung pats. However, due to the uneveness of dung deposi- tion it can contribute to the development of pasture gradients of composition and diver- sity associated to grazing.
Keywords: Central Spain; centro de españa; competencia; competition; dinámica de pastizales; disturbance; dung; excrementos; herbivores; herbívoros; pasture dynamics; perturbación

Le chêne blanc et le chêne vert, essences truffières par excellence - CHEVALIER, G. (Forêt Mediterranéenne, 1996)
Truffies grow in association with a num ber of deciduous and coniferous tree spe cies. However, not ail of these species offer the same interest for the cultivation of top quality truffles. The oaks (Quercus ssp) feature among the best symbiotic hosts for the truffle, as muchfor the longevity ofproduction asfor the quality of the truffles obtained. Downy oak (Q. pubescens) and holm oak (Q. ilex) are the truffle trees of the Périgord par excellence (T. de Tricastin, T. de Noria and Spoletto, T. melanospo rum ) , because they are the best adapted to the particular conditions of soil and clima te in which the mushroom develops. Furthermore, the morphology of their root system and their slow rate of growth facili tate optimal development of the mushroom in the soil. The downy oak - thermophilic, heliophi Lous, xerophilous to mesoxerophilous, hardy, lime- resistant - is adapted above alt to the production of the truffle of Périgord but is also suitable of obtaining other varieties of fine truffles, including the celebrated piedmont white truffle (T. magnatum). The holm oak, heliophilous, thermoxero philo us, hardy, with a wide range of habi tat is adapted above all to the production of the truffle of Périgord and the summer truffle (T. aesti vum ). Since 1973, sorne 850,000 downy and holm oaks and 250,000 hazels, innoculated with truffle mycorrhiza under the supervi sion of the INRA (French national agricul tural research body), have been planted in numerous areas in the south of France and even in the north. Studies have shown the superiority of the oak over the hazel, parti cularly with regard to the frequency and regularity of production. In respect to rapidity of coming into production, sorne holm oaks were as early as hazels (three and a halfyears after planting). Mycorrhiza-innoculated plants presently available appear, wh en planted, as very heterogenious (aspect, habit, yield) due to the fact that they are multiplied by sowing. Selecting of vegetatively reproduced plants is currently under way. One study is inves tigating whether in a "good producer" there exists a relationship between yield and certain ofils genetic characteristics.
Keywords: Chênes; Périgord (voyant); plants mycorhizés; Truffes

Le chêne blanc et le chêne vert, essences truffières par excellence - CHEVALIER, G (Forêt Mediterranéenne, 1996)
Truffies grow in association with a num ber of deciduous and coniferous tree spe cies. However, not ail of these species offer the same interest for the cultivation of top quality truffles. The oaks (Quercus ssp) feature among the best symbiotic hosts for the truffle, as muchfor the longevity ofproduction asfor the quality of the truffles obtained. Downy oak (Q. pubescens) and holm oak (Q. ilex) are the truffle trees of the Périgord par excellence (T. de Tricastin, T. de Noria and Spoletto, T. melanospo rum ) , because they are the best adapted to the particular conditions of soil and clima te in which the mushroom develops. Furthermore, the morphology of their root system and their slow rate of growth facili tate optimal development of the mushroom in the soil. The downy oak - thermophilic, heliophi Lous, xerophilous to mesoxerophilous, hardy, lime- resistant - is adapted above alt to the production of the truffle of Périgord but is also suitable of obtaining other varieties of fine truffles, including the celebrated piedmont white truffle (T. magnatum). The holm oak, heliophilous, thermoxero philo us, hardy, with a wide range of habi tat is adapted above all to the production of the truffle of Périgord and the summer truffle (T. aesti vum ). Since 1973, sorne 850,000 downy and holm oaks and 250,000 hazels, innoculated with truffle mycorrhiza under the supervi sion of the INRA (French national agricul tural research body), have been planted in numerous areas in the south of France and even in the north. Studies have shown the superiority of the oak over the hazel, parti cularly with regard to the frequency and regularity of production. In respect to rapidity of coming into production, sorne holm oaks were as early as hazels (three and a halfyears after planting). Mycorrhiza-innoculated plants presently available appear, wh en planted, as very heterogenious (aspect, habit, yield) due to the fact that they are multiplied by sowing. Selecting of vegetatively reproduced plants is currently under way. One study is inves tigating whether in a "good producer" there exists a relationship between yield and certain ofils genetic characteristics.
Keywords: Chênes; Périgord (voyant); plants mycorhizés; Truffes

Leaf and shoot growth dynamics of Quercus ilex L. - Gratani, L (ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY, 1996)
The vegetative activity of Quercus ilex L. takes place during the period of low water stress, directly following abundant rainfall at the end of winter. Low air temperature is the limiting factor for bud opening, while high air temperature influences specific leaf area (SLA) during the growth period. Net photosynthesis and stomatal conductance increase with a rise in leaf temperature up to 25 degrees C; whereas they decrease when leaf temperature is about 30 degrees C (at the end of May) and below 18 degrees C (November). SLA increases from the low maquis to the shrubby layer of the forest in response to the decreasing irradiance. The pattern of SLA shows peak values after bud break, which then decrease to a constant value. Shrubs in the evergreen forest exhibit a high SLA in May as a result of a double increase in leaf area, while leaf dry weight changes only slighly during the first expansion. The maximum relative growth rate (RGR) in May-June causes the leaf to reach about 90% of its definitive size and structure before the period of drought stress, ensuring that leaf expansion (the time of the greatest nutritional demand) is not adversely affected. The summer air temperatures reduce the relative growth rate, but do not completely block leaf expansion until September-October. Intraspecific variation of SLA reflects the phenotypic plasticity of Quercus ilex in different habitats and demonstrates its ability to respond adequately to changing environmental factors by altering leaf morphology.
Keywords: evergreen forest; Mediterranean; Quercus ilex L

Leaf Contamination by Atmospheric Pollutants as Assessed by Elemental Analysis of Leaf Tissue, Leaf Surface Deposit and Soil - Alfani, Anna; Maisto, Giulia; Iovieno, Paola; Rutigliano, Flora a; Bartoli, Giovanni (Journal of Plant Physiology, 1996)
In order to evaluate the influence of air pollutants influx on leaf elemental composition, the concentration ofN, S, Cu, Fe and Pb were analyzed in the surface deposit and tissue of Quercus ilex L. leaves from 8 sites of the urban area of Naples. The soil from the trunk base area of Q. ilex trees in the same sites was also analyzed for total contents of Nand S and for available contents ofCu, Fe and Pb. In the leafsurface deposit S content was high though significantly (P<O.OOl) lower than in the leaf tissue, whilst N was not detectable. Cu, Pb and Fe contents in leafsurface deposit were conspicuous. The Pb content was higher in the leafsurface deposit than in the leaf tissue. No correlation between leaftissue and surface deposit contents was found for S or for Fe. By contrast, positive and significant correlations (P < 0.01) were found between leaf deposit and leaf tissue for both Cu and Pb. Nand S contents in the leaves were not correlated to the respective contents in the soil and the same was also found for Cu and Fe. In contrast with the presence of limiting concentrations in the soil, N, S and Fe leaf contents were significantly higher than in the leaves from remote sites. The data suggest that direct uptake of airborne pollutants, in addition to root absorption, may influence leaf elemental composition of Q. ilex L. leaves.
The following values have no corresponding Zotero field: publisher: Gustav Fischer Verlag, Stuttgart
Keywords: air pollution; leaf contamination; nitrogen; Quercus ilex L; sulphur; Trace metals

Leaf Contamination by Atmospheric Pollutants as Assessed by Elemental Analysis of Leaf Tissue, Leaf Surface Deposit and Soil - Alfani, Anna; Maisto, Giulia; Iovieno, Paola; Rutigliano, Flora a.; Bartoli, Giovanni (Journal of Plant Physiology, 1996)
In order to evaluate the influence of air pollutants influx on leaf elemental composition, the concentration ofN, S, Cu, Fe and Pb were analyzed in the surface deposit and tissue of Quercus ilex L. leaves from 8 sites of the urban area of Naples. The soil from the trunk base area of Q. ilex trees in the same sites was also analyzed for total contents of Nand S and for available contents ofCu, Fe and Pb. In the leafsurface deposit S content was high though significantly (P<O.OOl) lower than in the leaf tissue, whilst N was not detectable. Cu, Pb and Fe contents in leafsurface deposit were conspicuous. The Pb content was higher in the leafsurface deposit than in the leaf tissue. No correlation between leaftissue and surface deposit contents was found for S or for Fe. By contrast, positive and significant correlations (P < 0.01) were found between leaf deposit and leaf tissue for both Cu and Pb. Nand S contents in the leaves were not correlated to the respective contents in the soil and the same was also found for Cu and Fe. In contrast with the presence of limiting concentrations in the soil, N, S and Fe leaf contents were significantly higher than in the leaves from remote sites. The data suggest that direct uptake of airborne pollutants, in addition to root absorption, may influence leaf elemental composition of Q. ilex L. leaves.
Keywords: air pollution; leaf contamination; nitrogen; Quercus ilex L; sulphur; Trace metals

Limitation of photosynthetic activity by CO2 availability in the chloroplasts of oak leaves from different species and during drought - Roupsard, O.; Gross, P.; Dreyer, E. (Ann. For. Sci., 1996)
It has recently been suggested that the low photosynthesis rates in tree species as compared to highly productive crops is at least partly due to resistances opposing the CO 2 fluxes in the mesophyll of tree leaves. To validate this assertion, values of CO2 mole fractions in the chloroplasts of leaves from Quercus petraea, Q robur, Q ilex and Populus sp were estimated on the basis of the analysis of the partitioning of light driven electron flow between fractions used for the carboxylation or the oxygenation of RuBP by Rubisco. The procedure used included: i) a measure of total light driven electron flows derived from the chlorophyll a fluorescence ratio ΔF/Fm', which is proportional to the photochemical efficiency of PS II, multiplied by incident irradiance and a calibration coefficient; ii) an estimation of the electron flux devoted to carboxylation obtained from net CO2 assimilation and respiration rate measurement, and using the known electron requirements (four electrons for CO2 or O2 fixation); iii) the derivation of the CO2 mole fraction in the chloroplasts from the specificity factor of Rubisco, and the ratio of carboxylation/oxygenation of RuBP. Results showed that in the absence of drought stress, the mole fraction of CO2 in the chloroplasts (35-45% of the atmospheric one) was much lower than the calculated substomatal one (60-70% of the atmospheric) in all species. Moreover, lowest values were recorded in the species with lowest assimilation rates, suggesting that the differences in the net CO 2 assimilation rate between species are linked to the CO2 availability in the chloroplasts. Finally, the CO2 availability decreased with increasing drought in the soil, stressing the importance of reduced influx of CO2 as an important factor for drought-induced declines of photosynthesis. These results are discussed with respect to the occurrence of significant resistances in the leaf mesophyll, in addition to the stomatal resistances.
Keywords: chlorophyll fluorescence; chloroplasts; CO2 diffusion; Drought; mesophyll conductance; oaks; Stomatal conductance

Limitation of photosynthetic activity by CO2 availability in the chloroplasts of oak leaves from different species and during drought - Roupsard, O; Gross, P; Dreyer, E (Ann. For. Sci., 1996)
It has recently been suggested that the low photosynthesis rates in tree species as compared to highly productive crops is at least partly due to resistances opposing the CO 2 fluxes in the mesophyll of tree leaves. To validate this assertion, values of CO2 mole fractions in the chloroplasts of leaves from Quercus petraea, Q robur, Q ilex and Populus sp were estimated on the basis of the analysis of the partitioning of light driven electron flow between fractions used for the carboxylation or the oxygenation of RuBP by Rubisco. The procedure used included: i) a measure of total light driven electron flows derived from the chlorophyll a fluorescence ratio ΔF/Fm', which is proportional to the photochemical efficiency of PS II, multiplied by incident irradiance and a calibration coefficient; ii) an estimation of the electron flux devoted to carboxylation obtained from net CO2 assimilation and respiration rate measurement, and using the known electron requirements (four electrons for CO2 or O2 fixation); iii) the derivation of the CO2 mole fraction in the chloroplasts from the specificity factor of Rubisco, and the ratio of carboxylation/oxygenation of RuBP. Results showed that in the absence of drought stress, the mole fraction of CO2 in the chloroplasts (35-45% of the atmospheric one) was much lower than the calculated substomatal one (60-70% of the atmospheric) in all species. Moreover, lowest values were recorded in the species with lowest assimilation rates, suggesting that the differences in the net CO 2 assimilation rate between species are linked to the CO2 availability in the chloroplasts. Finally, the CO2 availability decreased with increasing drought in the soil, stressing the importance of reduced influx of CO2 as an important factor for drought-induced declines of photosynthesis. These results are discussed with respect to the occurrence of significant resistances in the leaf mesophyll, in addition to the stomatal resistances.
Keywords: chlorophyll fluorescence; chloroplasts; CO2 diffusion; Drought; mesophyll conductance; oaks; Stomatal conductance

Litterfall and mineral return in two cork-oak forests in northeast spain - Caritat, A; Bertoni, G; Molinas, M; Oliva, M; Domínguez-Planella, A (Ann. For. Sci., 1996)
Seasonal trends in littertall and potential mineral return were studied in two cork-oak forest sites in the northeastern Iberian peninsula. The estimated average litter production was 3.9 Mg.ha-1.year -1 for one site and 4.6 Mg.ha-1.year-1 for the other; these figures are similar to those reported for holm-oak (Quercus ilex) forests in the same area. Seasonal litterfall patterns were typical of Mediterranean forest ecosystems. Leaves accounted for 46 to 78% of the total dry matter. Their annual weighted-average mineral composition was low in macronutrients (N 8-9; K 4-5; Mg 0.8-1.3; Ca 9-10 and P 0.4-1 mg.g-1) and relatively high in micronutrients such as Mn (2-2.2 mg.g-1) or Fe (0.3-0.4 mg.g-1). Minimum N and P concentrations were found during the growth period. Estimates of potential mineral return for an annual cycle were N 38-52, P 2.1-5.2, K 20-28, Ca 44-53 and Mg 5.4-5.0 kg.ha -1, depending on the site biomass and fertility.
Keywords: cork-oak; litterfall; Mediterranean forest ecosystems; nutrient cycling; Quercus suber

Litterfall and mineral return in two cork-oak forests in northeast spain - Caritat, A.; Bertoni, G.; Molinas, M.; Oliva, M.; Domínguez-Planella, A. (Ann. For. Sci., 1996)
Seasonal trends in littertall and potential mineral return were studied in two cork-oak forest sites in the northeastern Iberian peninsula. The estimated average litter production was 3.9 Mg.ha-1.year -1 for one site and 4.6 Mg.ha-1.year-1 for the other; these figures are similar to those reported for holm-oak (Quercus ilex) forests in the same area. Seasonal litterfall patterns were typical of Mediterranean forest ecosystems. Leaves accounted for 46 to 78% of the total dry matter. Their annual weighted-average mineral composition was low in macronutrients (N 8-9; K 4-5; Mg 0.8-1.3; Ca 9-10 and P 0.4-1 mg.g-1) and relatively high in micronutrients such as Mn (2-2.2 mg.g-1) or Fe (0.3-0.4 mg.g-1). Minimum N and P concentrations were found during the growth period. Estimates of potential mineral return for an annual cycle were N 38-52, P 2.1-5.2, K 20-28, Ca 44-53 and Mg 5.4-5.0 kg.ha -1, depending on the site biomass and fertility.
Keywords: cork-oak; litterfall; Mediterranean forest ecosystems; nutrient cycling; Quercus suber

Lixiviation as a tool for radionuclide fractionation in holm oak leaves - Tent, J.; Rauret, G. (JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY-ARTICLES, 1996)
A sequential extraction scheme, using distilled water and chloroform : hexane(1:2) was applied in a study of radionuclide retention by helm oak leaves. To perform this study, holm oak leaves were contaminated by dry deposition using a thermogenerated radioactive aerosol containing Cs-134, Sr-85 and Ag-110m. The experimental parameters tested were: type and lime of shaking, number of successive extractions in each step, and the volume of extractans. From the results obtained, two schemes which give complementary information about radionuclide retention are proposed. The first scheme, using a single water extraction with mechanical shaking, allows us to define two fractions: the fraction removed by water, which is related to total radionuclide retention on leaf surfaces, and the residual fraction, which is associated with radionuclides incorporated into the leaves. The second scheme is based on a two-step extraction with manual shaking using water and chloroform :hexane, and permits us to distinguish among three fractions:the fraction removed by water(which is related to the radionuclide fraction easily leached by rain), the fraction removed by organic solvent (which is associated with the radionuclide fraction strongly retained on leaf surface), and the residual fraction, which may represent the absorbed radionuclide content. Since our objective was to study the retention of Cs-134, Sr-85 and Ag-110m, simultaneously, the experimental conditions chosen were a compromise of individual suitable conditions for each radionuclide.
APSAPSThe following values have no corresponding Zotero field: pub-location: PO BOX 245, H-1519 BUDAPEST, HUNGARY publisher: AKADEMIAI KIADO
Keywords: Holm oak; radionuclide

Lixiviation as a tool for radionuclide fractionation in holm oak leaves - Tent, J; Rauret, G (JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY-ARTICLES, 1996)
A sequential extraction scheme, using distilled water and chloroform : hexane(1:2) was applied in a study of radionuclide retention by helm oak leaves. To perform this study, holm oak leaves were contaminated by dry deposition using a thermogenerated radioactive aerosol containing Cs-134, Sr-85 and Ag-110m. The experimental parameters tested were: type and lime of shaking, number of successive extractions in each step, and the volume of extractans. From the results obtained, two schemes which give complementary information about radionuclide retention are proposed. The first scheme, using a single water extraction with mechanical shaking, allows us to define two fractions: the fraction removed by water, which is related to total radionuclide retention on leaf surfaces, and the residual fraction, which is associated with radionuclides incorporated into the leaves. The second scheme is based on a two-step extraction with manual shaking using water and chloroform :hexane, and permits us to distinguish among three fractions:the fraction removed by water(which is related to the radionuclide fraction easily leached by rain), the fraction removed by organic solvent (which is associated with the radionuclide fraction strongly retained on leaf surface), and the residual fraction, which may represent the absorbed radionuclide content. Since our objective was to study the retention of Cs-134, Sr-85 and Ag-110m, simultaneously, the experimental conditions chosen were a compromise of individual suitable conditions for each radionuclide.
APS
Keywords: Holm oak; radionuclide

Local variations of ecosystem functions in Mediterranean evergreen oak woodland - Joffre, R; Rambal, S; Romane, F (Ann. For. Sci., 1996)
The spatial variation of ecosystem function was studied in a Quercus ilex coppice growing on hard limestone with low soil water availability. Spatial structures obtained from data on i) leaf area index, ii) leaf litterfall, and iii) leaf litter decay rate were compared. All these variables were sampled on 26 points located within a 30 x 30 m plot. Mean average leaf litterfall over 10 years (1984-1993) was 254 g.m-2. For each year, the semivariograms of leaf litterfall have been fitted using a spherical model. The values of the range parameter (indicating the limit of the spatial dependence) ranged from 6.4 to 10.3 m, very close to the value (9.2 m) of the range parameter obtained when fitting the semivariogram of mean leaf litterfall over 10 years. This result indicates the temporal persistence of the spatial pattern of leaf litterfall. The leaf area index (LAI) was estimated at the same points with a plant canopy analyzer. The mean value was 2.96 ± 0.30. The limit of spatial dependence for LAI was very close to that obtained for leaf litterfall (range = 8.5 m). The litter decomposition pattern was obtained through analysis of litter samples taken at the same points. The percentage of ash-free litter mass remaining (LMR) estimated using near-infrared reflectance spectroscopy indicates the stage of decomposition. It decreased strongly between the surface (mean value 85.6%) and the subsurface layers (mean value 63.4%). The two semivariograms can be described by spherical models, the sill being reached at a range of 21.4 and 18.7 m for the surface and subsurface layers, respectively. The two variables directly related to the structure of the canopy (LAI and leaf litterfall) exhibited close spatial dependence and differed from the soil process-related variables (stage of decomposition) whose ranges were approximately double. These geostatistical analyses show promise for use in developing hypotheses concerning the spatial scale of process-pattern interactions.
Keywords: decomposition; geostatistics; leaf area index; litterfall; local variation; Quercus ilex

Long-term exposure to elevated in a natural Quercus ilex L. community: net photosynthesis and photochemical efficiency of PSII at different levels of water stress - Scarascia-Mugnozza, G (Plant, Cell & Environment, 1996)
Naturally grown trees of Mediterranean evergreen oak (Quercus ilex L.), representing tbe climax species of tbe region, were enclosed in six large open-top chambers and exposed to ambient and elevated CO2 concentrations during a 3 year period. Maximum daily net photosynthetic rates measured at the two different CO2 concentrations were from 30 to 100% higher in elevated than in ambient [CO2] throughout the experimental period. The increase in maximum daily photosynthesis was also accompanied by a 93% rise in the apparent quantum yield of CO2 assimilation, measured during periods of optimum soil moisture conditions. Hence, no clear evidence of downregulation of net photosynthetic activity was found. Interactions between atmospheric CO2 concentration and plant water stress were studied by following the natural evolution of drought in different seasons and years. At each level of water stress, the maximum rate of carbon assimilation was higher in elevated than in ambient [CO2I by up to 100%. Analysis of in vivo chlorophyll fluorescence parameters in normal (21%) and low (2%) oxygen concentrations provided useful insights into the functioning and stability of the photosynthetic processes. The photochemical efficiency of PSII (Fy/F„,) progressively decreased as drought conditions became more evident; this trend was accentuated under elevated tCO2]. Thermal de-excitation processes were possibly more significant under elevated than Under ambient [CO2], in a combination of environmental stresses. This research suggests two possible conclusions: (i) a 'positive' interaction between elevated [CO2] and carbon metabolism can be obtained through relief of water stress limitation in the summer months, and (ii) elevated [CO2], under drought conditions, may also enhance the significance of slow-relaxing quenching.
Keywords: chlotophyll fluorescenee; elevated [CO2]; Mediterranean ecosystems; photosynthesis; Quercus ilex L.; water stress

Mammals and fire in mediterranean ecosystems Ecological responses from the shrew Crocidura russula (Insectivora Soricidae) and the rodent Eliomys quercinus (Gliridae) in burned cork oak forest - Fons, R; Grabulosa, I; Marchand, B; Miquel, J; Feliu, C; Mas-Coma, S (VIE ET MILIEU-LIFE AND ENVIRONMENT, 1996)
Mammals and fire in mediterranean ecosystems. Ecological responses from the shrew Crocidura russula (Insectivora - Soricidae) and the rodent Eliomys quercinus (Gliridae) in burned crock oak forest. In the present work we report the ecological responses of two small mammals to fire. During a six-year post-fire period, both species were studied by the capture-mark-recapture on a 9 ha quadrate established in a recently burned cork oak forest. The white-toothed-shrew, Crocidura russula, was the least resistant species to fire, disappearing completely during the first two years. Reappearing on the third year, the population maintained a low effective with the same fluctuation similar to that observed within the control. Although faster than on other studied mediterranean ecosystems, its allochthonous ristablishment on the burned cork oak forest, seems to be dependent on the litter reconstitution. Due to its rupicolous habits, its biotope specialization, highly favored by the presence of rocks on the capture quadrate, and some physiological apects (hibernation), the dormouse Eliomys quercinus, showed a better pre-adaptive response to the post-fire stress. The survival of a nucleus of autochtonous individuals insured, from the first year, a slow, but progressive recovery of the population.
Keywords: Cork Oak Forest; Crocidura russula; ELIOMYS QUERCINUS; fire; mammals

Mammals and fire in mediterranean ecosystems Ecological responses from the shrew Crocidura russula (Insectivora Soricidae) and the rodent Eliomys quercinus (Gliridae) in burned cork oak forest - Fons, R.; Grabulosa, I.; Marchand, B.; Miquel, J.; Feliu, C.; Mas-Coma, S. (VIE ET MILIEU-LIFE AND ENVIRONMENT, 1996)
Mammals and fire in mediterranean ecosystems. Ecological responses from the shrew Crocidura russula (Insectivora - Soricidae) and the rodent Eliomys quercinus (Gliridae) in burned crock oak forest. In the present work we report the ecological responses of two small mammals to fire. During a six-year post-fire period, both species were studied by the capture-mark-recapture on a 9 ha quadrate established in a recently burned cork oak forest. The white-toothed-shrew, Crocidura russula, was the least resistant species to fire, disappearing completely during the first two years. Reappearing on the third year, the population maintained a low effective with the same fluctuation similar to that observed within the control. Although faster than on other studied mediterranean ecosystems, its allochthonous ristablishment on the burned cork oak forest, seems to be dependent on the litter reconstitution. Due to its rupicolous habits, its biotope specialization, highly favored by the presence of rocks on the capture quadrate, and some physiological apects (hibernation), the dormouse Eliomys quercinus, showed a better pre-adaptive response to the post-fire stress. The survival of a nucleus of autochtonous individuals insured, from the first year, a slow, but progressive recovery of the population.
The following values have no corresponding Zotero field: pub-location: LABORATOIRE ARAGO, BP 44, 66651 BANYULS-SUR-MER CEDEX, FRANCE publisher: OBSERVATOIRE OCEANOLOGIQUE BANYULS
Keywords: Cork Oak Forest; Crocidura russula; ELIOMYS QUERCINUS; fire; mammals

Micrometeorological assessment of sensitivity of canopy resistance to vapour pressure deficit in a Mediterranean oak forest - Pitacco, A; Gallinaro, N (Ann. For. Sci., 1996)
Canopy surface resistance to water vapour (rc) of an extensive Quercus ilex L stand (Bosco Mesola, northeast Italy) has been evaluated by inverting the Penman-Monteith equation. The latent heat flux was estimated by applying the Bowen ratio-energy budget micrometeorological method. A linear relationship was found between rc and the vapour pressure deficit. Canopy resistance increased regularly during the day and that yielded a recurring diurnal pattern of energy partitioning where most of the latent heat was dissipated in the early morning and the release of sensible heat increased after midday. This behaviour has been confirmed also by independent estimates of transpiration, based on measurements of sap flow velocity in small branches. Ecological consequences of this feature are briefly discussed applying the concept of coupling between canopy and atmosphere
Keywords: canopy resistance; energy balance; Evapotranspiration; Quercus ilex L; sap flow