<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Oliveira, G</style></author><author><style face="normal" font="default" size="100%">Penuelas, J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Effects of winter cold stress on photosynthesis and photochemical efficiency of PSII of the Mediterranean Cistus albidus L. and Quercus ilex L.</style></title><secondary-title><style face="normal" font="default" size="100%">Plant Ecology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">evergreen</style></keyword><keyword><style  face="normal" font="default" size="100%">Fv/Fm</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean winter</style></keyword><keyword><style  face="normal" font="default" size="100%">photoinhibition</style></keyword><keyword><style  face="normal" font="default" size="100%">semi-deciduous</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2004</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2004///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.springerlink.com/index/GV5P7326829Q0GK6.pdf</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">175</style></volume><pages><style face="normal" font="default" size="100%">179 - 191</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">This study examined the photosynthetic and growth performances of potted plants of Cistus albidus L. and Quercus ilex L. submitted either to natural Mediterranean winter conditions or to mild greenhouse conditions. Plants grown outdoors exhibited lower light and CO2 -saturated CO2 assimilation rates Asat and apparent quantum yield i than those indoors. Until mid-winter, C. albidus had higher Asat than Q. ilex, but differences disappeared after a period of severe cold. Maximal photochemical efficiency of PSII Fv/Fm measured predawn was higher in C. albidus than in Q. ilex, and decreased throughout the season in outdoor plants. Fv/Fm also decreased at light saturation Asat in both species. Fv/Fm was correlated with photosynthetic capacity and efficiency quantum yield, but the resulting regression slopes were different between the two species. At the physiological level, C. albidus seemed to cope better with cold stress than Q. ilex. However, winter stress induced reduction of leaf absorptance, increased leaf mass per area, extensive leaf damage and high plant mortality in C. albidus. This suggests that the high performance of C. albidus leaves is not likely to be maintained for long periods of cold stress, and may therefore depend on continuous leaf replacement. Quercus ilex showed a conservative behaviour, with low net assimilation rates but greater leaf and plant survival than C. albidus.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Oliveira, G</style></author><author><style face="normal" font="default" size="100%">Penuelas, J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Comparative protective strategies of Cistus albidus and Quercus ilex facing photoinhibitory winter conditions</style></title><secondary-title><style face="normal" font="default" size="100%">Environmental and experimental botany</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">evergreen</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf angle</style></keyword><keyword><style  face="normal" font="default" size="100%">manipulation</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean winter</style></keyword><keyword><style  face="normal" font="default" size="100%">photoprotection</style></keyword><keyword><style  face="normal" font="default" size="100%">semideciduous</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2002</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2002///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.sciencedirect.com/science/article/pii/S0098847202000035</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">47</style></volume><pages><style face="normal" font="default" size="100%">281 - 289</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The role of structural photoprotection under photoinhibitory winter conditions was evaluated in two Mediterranean woody species: Cistus albidus (semideciduous) and Quercus ilex (evergreen). Shoots were manipulated in order to modify the light load naturally received by the leaves throughout the cold season, and monitored for changes in maximum photochemical efﬁciency of PSII, phenology, and leaf morphology. Naturally steep leaves of C. albidus were restrained to a horizontal position, and compared with control leaves (naturally horizontal, or steeply inclined). Fully exposed leaves of Q. ilex were artiﬁcially protected through partial shading, and compared with control leaves (not shaded). During the cold season, the most exposed (either naturally or artiﬁcially) leaves were always more photoinhibited (had lower maximal photochemical efﬁciency of PSII) than the photoprotected ones. The differences disappeared at the beginning of spring. Winter photoinhibition was not more pronounced in older than in younger leaves of C. albidus, indicating that inclination rather than age affected their photochemical efﬁciency. Leaf chlorophyll contents were not signiﬁcantly affected by the manipulations. Leaf thickness decreased slightly in the least exposed shoots of the evergreen species, but no changes were detected in leaf morphological traits of the semideciduous one. The increased photoinhibitory pressure led only to slight and non-signiﬁcant changes in phenology and growth</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Oliveira, G</style></author><author><style face="normal" font="default" size="100%">Martins-Loução, MA</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">CUSTOS ASSOCIADOS AO CRESCIMENTO DE FOLHAS E CAULES EM SOBREIRO E AZINHEIRA</style></title><short-title><style face="normal" font="default" size="100%">Revista de biologia</style></short-title></titles><dates><year><style  face="normal" font="default" size="100%">2002</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2002</style></date></pub-dates></dates><publisher><style face="normal" font="default" size="100%">Instituto Botánica, Faculdade</style></publisher><volume><style face="normal" font="default" size="100%">20</style></volume><pages><style face="normal" font="default" size="100%">29 - 36</style></pages><isbn><style face="normal" font="default" size="100%">0034-7736</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Oliveira, G</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">A outra face do descortiçamento: Implicaçoes para a fisiologia e crescimento do sobreiro</style></title><short-title><style face="normal" font="default" size="100%">Fragmentos de Ecologia, Lisboa</style></short-title></titles><dates><year><style  face="normal" font="default" size="100%">2002</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2002</style></date></pub-dates></dates><pages><style face="normal" font="default" size="100%">307 - 320</style></pages><language><style face="normal" font="default" size="100%">eng</style></language></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Oliveira, G</style></author><author><style face="normal" font="default" size="100%">Penuelas, J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Allocation of absorbed light energy into photochemistry and dissipation in a semi-deciduous and an evergreen Mediterranean woody species during winter</style></title><secondary-title><style face="normal" font="default" size="100%">AUSTRALIAN JOURNAL OF PLANT PHYSIOLOGY</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">chlorophyll fluorescence</style></keyword><keyword><style  face="normal" font="default" size="100%">Cistus albidus L.</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2001</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2001///</style></date></pub-dates></dates><publisher><style face="normal" font="default" size="100%">C S I R O PUBLISHING</style></publisher><pub-location><style face="normal" font="default" size="100%">150 OXFORD ST, PO BOX 1139, COLLINGWOOD, VICTORIA 3066, AUSTRALIA</style></pub-location><volume><style face="normal" font="default" size="100%">28</style></volume><pages><style face="normal" font="default" size="100%">471 - 480</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The importance of photodissipation in the protection from excessive solar energy absorption during winter was evaluated in shrubs of Cistus albidus L. (semi-deciduous) and Quercus ilex L. (evergreen). Diurnal and seasonal changes in chlorophyll a (Chl a) fluorescence-related parameters of leaves with different microclimates (south- and north-facing leaves) were assessed from early winter to late spring in a Mediterranean plant community. Maximal photochemical efficiency of photosystem II (PSII) (F-v/F-m) was lowest on sunny and cold winter days, but low values on overcast (and cold) days indicated that the whole winter season was potentially stressful. Photoinhibition was greater in south than in north leaves during winter. There was a decreased proportion of absorbed light utilised in photochemistry, and an increase in that proportion diverted into dissipation processes on cold sunny days. Under low light conditions (e.g. of north-facing leaves throughout the winter, or all the canopy on overcast days), a greater proportion of light energy was allocated to photochemistry than in bright conditions, although still smaller than the dissipated fraction. Allocation to photochemistry prevailed over dissipation only in spring. The phenological and structural characteristics of C. albidus protect it from excessive light loads, and reduce the need for investment in physiological mechanisms to avoid their harmful effects. Quercus ilex lacks such protection, and relies essentially on increased and sustained photodissipative activity at the physiological level.</style></abstract><issue><style face="normal" font="default" size="100%">6</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Oliveira, G</style></author><author><style face="normal" font="default" size="100%">Penuelas, J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Comparative photochemical and phenomorphological responses to winter stress of an evergreen ( Quercus ilex L.) and a semi-deciduous ( Cistus albidus</style></title><secondary-title><style face="normal" font="default" size="100%">Acta Oecologica</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Chlorophyll ﬂuorescence</style></keyword><keyword><style  face="normal" font="default" size="100%">evergreens</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf characteristics</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean winter</style></keyword><keyword><style  face="normal" font="default" size="100%">Phenology</style></keyword><keyword><style  face="normal" font="default" size="100%">photoinhibition</style></keyword><keyword><style  face="normal" font="default" size="100%">semi-deciduous</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2000</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2000///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.sciencedirect.com/science/article/pii/S1146609X00001211</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">21</style></volume><pages><style face="normal" font="default" size="100%">97 - 107</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The impact of winter stress on plants from a Mediterranean area was evaluated through comparison of photosystem II (PS II) efficiencies and phenomorphological characteristics of two Mediterranean woody species – Quercus ilex (evergreen) and Cistus albidus (semi-deciduous). The studies were carried out in NE Spain, at two sites with different mean winter temperatures. The results showed that reductions of the efficiency of PS II may occur in Mediterranean plant communities during winter, and are especially remarkable on colder days. The extent and duration of the decrease in PS II efficiency (photoinhibition) depended not only on the climatic conditions, but also on the site, on the species considered and on the position of leaves in the plant canopy. Increased photoinhibition at the colder site was only clear for C. albidus. Nevertheless, the efficiencies of PS II were always higher in C. albidus than in Q. ilex. Phenological patterns, morphology and leaf inclination may protect C. albidus leaves from potentially photoinhibitory conditions in winter. Morphological and structural photoprotection is apparently not so well developed in Q. ilex, which probably relies more on increased protection at the photochemical level of its long-lived leaves. As has been reported in relation to summer-drought stress, Q. ilex has possibly developed a strategy of tolerance to photoinhibition, whereas C. albidus relies preferentially on avoidance features</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Oliveira, G</style></author><author><style face="normal" font="default" size="100%">Werner, C</style></author><author><style face="normal" font="default" size="100%">Correia, O</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Are ecophysiological responses influenced by crown position in cork-oak?</style></title><secondary-title><style face="normal" font="default" size="100%">Ann. For. Sci.</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">cork-oak</style></keyword><keyword><style  face="normal" font="default" size="100%">isolated tree</style></keyword><keyword><style  face="normal" font="default" size="100%">microclimate</style></keyword><keyword><style  face="normal" font="default" size="100%">Stomatal conductance</style></keyword><keyword><style  face="normal" font="default" size="100%">within-crown variability</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1996</style></year></dates><volume><style face="normal" font="default" size="100%">53</style></volume><pages><style face="normal" font="default" size="100%">235-241</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">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.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Oliveira, G</style></author><author><style face="normal" font="default" size="100%">Werner, C</style></author><author><style face="normal" font="default" size="100%">Correia, O</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Are ecophysiological responses influenced by crown position in cork-oak?</style></title><secondary-title><style face="normal" font="default" size="100%">Ann. For. Sci.</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">cork-oak</style></keyword><keyword><style  face="normal" font="default" size="100%">isolated tree</style></keyword><keyword><style  face="normal" font="default" size="100%">microclimate</style></keyword><keyword><style  face="normal" font="default" size="100%">Stomatal conductance</style></keyword><keyword><style  face="normal" font="default" size="100%">within-crown variability</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1996</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1996///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://dx.doi.org/10.1051/forest:19960206</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">53</style></volume><pages><style face="normal" font="default" size="100%">235 - 241</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">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.</style></abstract><issue><style face="normal" font="default" size="100%">2-3</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Oliveira, G</style></author><author><style face="normal" font="default" size="100%">Martins-Loução, M a</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Nutrient dynamics in crown tissues of cork-oak (Quercus suber L?.)</style></title><secondary-title><style face="normal" font="default" size="100%">Trees-Structure and …</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Evergreen oaks</style></keyword><keyword><style  face="normal" font="default" size="100%">macronutrients</style></keyword><keyword><style  face="normal" font="default" size="100%">montado</style></keyword><keyword><style  face="normal" font="default" size="100%">seasonal patterns</style></keyword><keyword><style  face="normal" font="default" size="100%">tissue nutrient contents</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1996</style></year></dates><volume><style face="normal" font="default" size="100%">10</style></volume><pages><style face="normal" font="default" size="100%">247-254</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The seasonal fluctuation of N, P, K, Ca and Mg in leaves, young stems and fruits of young and mature Quercus suber trees growing at the same site was studied. Nutrient dynamics within the tree appeared to be linked to phenological events. Leaves maximized their nutrient con- tents throughout summer whereas stems maintained rather constant values during most of the year. Before the spring growth flush they apparently acted as temporary reservoirs for some nutrients, translocated from leaves or other organs, so that such nutrients would be easily invested in the new tissues. A significant investment was made in sink organs like flowers and fruits. The tree probably relies not only on leaves but also on other nutrient reservoirs like older branches and roots for an adequate supply to those sinks and to the spring growth. The importance of the sampling dates and the basis of expression used for nutrient concen- trations has also been emphasized. Nutrient contents and seasonal trends of the studied trees were similar to those of other evergreen oaks, although somewhat higher values for N, K, and Mg were found. Moreover, soil nutrient contents in the studied &quot;montado&quot; were much lower than in other Iberic oak stands. However the nutrient status and require- ments of cork-oak suggest high (or at least adequate) nutrient availability to the trees. The mechanisms by which this could be achieved are discussed.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Oliveira, G</style></author><author><style face="normal" font="default" size="100%">Martins-Loução, M a</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Nutrient dynamics in crown tissues of cork-oak (Quercus suber L?.)</style></title><secondary-title><style face="normal" font="default" size="100%">Trees-Structure and …</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Evergreen oaks</style></keyword><keyword><style  face="normal" font="default" size="100%">macronutrients</style></keyword><keyword><style  face="normal" font="default" size="100%">montado</style></keyword><keyword><style  face="normal" font="default" size="100%">seasonal patterns</style></keyword><keyword><style  face="normal" font="default" size="100%">tissue nutrient contents</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1996</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1996///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.springerlink.com/index/q29gp8tjeymuh2kx.pdf</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">10</style></volume><pages><style face="normal" font="default" size="100%">247 - 254</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The seasonal fluctuation of N, P, K, Ca and Mg in leaves, young stems and fruits of young and mature Quercus suber trees growing at the same site was studied. Nutrient dynamics within the tree appeared to be linked to phenological events. Leaves maximized their nutrient con- tents throughout summer whereas stems maintained rather constant values during most of the year. Before the spring growth flush they apparently acted as temporary reservoirs for some nutrients, translocated from leaves or other organs, so that such nutrients would be easily invested in the new tissues. A significant investment was made in sink organs like flowers and fruits. The tree probably relies not only on leaves but also on other nutrient reservoirs like older branches and roots for an adequate supply to those sinks and to the spring growth. The importance of the sampling dates and the basis of expression used for nutrient concen- trations has also been emphasized. Nutrient contents and seasonal trends of the studied trees were similar to those of other evergreen oaks, although somewhat higher values for N, K, and Mg were found. Moreover, soil nutrient contents in the studied &quot;montado&quot; were much lower than in other Iberic oak stands. However the nutrient status and require- ments of cork-oak suggest high (or at least adequate) nutrient availability to the trees. The mechanisms by which this could be achieved are discussed.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>47</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Oliveira, G</style></author><author><style face="normal" font="default" size="100%">Werner, C</style></author><author><style face="normal" font="default" size="100%">Mertens, C</style></author><author><style face="normal" font="default" size="100%">Correia, O</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">INFLUENCIA DE LA POSICION DE LA COPA SOBRE LA FENOLOGIA y LAS RELACIONES HIDRICAS DEL ALCORNOQUE (QUERCUS SUBER L.)</style></title><secondary-title><style face="normal" font="default" size="100%">Congreso Forestal Español, Lourizán - Pontevedra. 1993</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Crown position</style></keyword><keyword><style  face="normal" font="default" size="100%">Phenology</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber</style></keyword><keyword><style  face="normal" font="default" size="100%">Stomatal eonductance 1)</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1993</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1993///</style></date></pub-dates></dates><pages><style face="normal" font="default" size="100%">277 - 282</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">A tree crown may be seen as a large and heterogeneous population of branches and leaves, unequally subjected to the environmental factors. It is thus questionable if studies on a few leaves or a branch will be a good approach to the whole canopy. This is particularly important in the field, where the applieation of ecophysiological measurements to mature (and generally large) trees presents obvious human and financial problems. The purpose of this study was to determine the effeet of different levels and directions within the' crown on the phenology and water relations of a typieal cork-oak in south Portugal. Our preliminary results show that the parts of the erown exposed to higher radiation value~ present a stronger growth and biomass production (direetion effect). Crown level was not clearly related to the results, suggesting that the &quot;height effect&quot; is not very important in trees with wide and diffuse crowns like the ones occurring in the montado systems.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>3</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Oliveira, G</style></author><author><style face="normal" font="default" size="100%">Werner, C</style></author><author><style face="normal" font="default" size="100%">Mertens, C</style></author><author><style face="normal" font="default" size="100%">Correia, O</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">INFLUENCIA DE LA POSICION DE LA COPA SOBRE LA FENOLOGIA y LAS RELACIONES HIDRICAS DEL ALCORNOQUE (QUERCUS SUBER L.)</style></title><secondary-title><style face="normal" font="default" size="100%">Congreso Forestal Español, Lourizán - Pontevedra. 1993</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Crown position</style></keyword><keyword><style  face="normal" font="default" size="100%">Phenology</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber</style></keyword><keyword><style  face="normal" font="default" size="100%">Stomatal eonductance 1)</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1993</style></year></dates><pages><style face="normal" font="default" size="100%">277-282</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">A tree crown may be seen as a large and heterogeneous population of branches and leaves, unequally subjected to the environmental factors. It is thus questionable if studies on a few leaves or a branch will be a good approach to the whole canopy. This is particularly important in the field, where the applieation of ecophysiological measurements to mature (and generally large) trees presents obvious human and financial problems. The purpose of this study was to determine the effeet of different levels and directions within the' crown on the phenology and water relations of a typieal cork-oak in south Portugal. Our preliminary results show that the parts of the erown exposed to higher radiation value~ present a stronger growth and biomass production (direetion effect). Crown level was not clearly related to the results, suggesting that the &quot;height effect&quot; is not very important in trees with wide and diffuse crowns like the ones occurring in the montado systems.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>47</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Oliveira, G</style></author><author><style face="normal" font="default" size="100%">Werner, C</style></author><author><style face="normal" font="default" size="100%">Mertens, C</style></author><author><style face="normal" font="default" size="100%">Correia, O</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Influencias de la posición de la copa sobre la fenología y las relaciones hídricas del alcornoque (Quercus suber L.)</style></title><short-title><style face="normal" font="default" size="100%">Congresos-CARGA FINAL</style></short-title></titles><dates><year><style  face="normal" font="default" size="100%">1993</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1993</style></date></pub-dates></dates><language><style face="normal" font="default" size="100%">eng</style></language></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Correia, O A</style></author><author><style face="normal" font="default" size="100%">Oliveira, G</style></author><author><style face="normal" font="default" size="100%">Martins-Loução, M a</style></author><author><style face="normal" font="default" size="100%">Catarino, F M</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Effects of bark-stripping on the water relations of Quercus suber L</style></title><secondary-title><style face="normal" font="default" size="100%">Scientia gerundensis</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">bark-stripping</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber</style></keyword><keyword><style  face="normal" font="default" size="100%">Transpiration</style></keyword><keyword><style  face="normal" font="default" size="100%">water relations</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1992</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1992///</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">18</style></volume><pages><style face="normal" font="default" size="100%">195 - 204</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Quercus suber is the primary source of industrial cork and can produce cork every 9-10 years. The main objective of this work was to investigate the influence of bark stripping on the stomatal activity and water relations of cork-oak. For this purpose, diurnal changes on transpiration, stomatal conductance and water potencial were measured before and after bark stripping during July and August 1989 and 1990. The stripping on the trees had been done at various intensities. The water loss by the stripped surface was also measured. These results show that severe bark-stripping may lead to a decrease in stomatal conductance and considerable water losses. The stripping stress is not clearly dependent on the stripping coefficients, but rather on the water lost by the trunk which varies from tree to tree probably according to the phloemic tissues composition.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>5</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Oliveira, G</style></author><author><style face="normal" font="default" size="100%">Correia, OA</style></author><author><style face="normal" font="default" size="100%">Martins-Loução, MA</style></author><author><style face="normal" font="default" size="100%">Catarino, FM</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Growth patterns of cork-oak (Quercus suber L.) under natural conditions</style></title><secondary-title><style face="normal" font="default" size="100%">Responses of Forest Ecosystems to Environmental Changes</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">1992</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1992</style></date></pub-dates></dates><publisher><style face="normal" font="default" size="100%">Springer</style></publisher><pages><style face="normal" font="default" size="100%">858 - 860</style></pages><isbn><style face="normal" font="default" size="100%">1851668780</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Oliveira, G</style></author><author><style face="normal" font="default" size="100%">Correia, O A</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Water relations of crok-oak (Quercus suber L.) under natural conditions</style></title><secondary-title><style face="normal" font="default" size="100%">Plant Ecology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Mediterranean climate</style></keyword><keyword><style  face="normal" font="default" size="100%">montado</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber</style></keyword><keyword><style  face="normal" font="default" size="100%">soil-to-leaf hydraulic conductivity</style></keyword><keyword><style  face="normal" font="default" size="100%">Stomatal conductance</style></keyword><keyword><style  face="normal" font="default" size="100%">Transpiration</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1992</style></year></dates><volume><style face="normal" font="default" size="100%">99-100</style></volume><pages><style face="normal" font="default" size="100%">199-208</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Daily and annual courses of leaf transpiration, stomatal conductance and shoot water potential of four Quercus suber individuals were compared in a semi-natural stand in southwest Portugal, from spring 1989 to early summer 1990. The trees investigated showed annual patterns typical of evergreen sclerophyllous species but varied in their range of stomatal operation. This appeared to be related to differences in hydraulic conductiv- ity in the root-to-leaf pathway. Maximum stomatal conductance and transpiration rates occurred from March to June. Water stress was found to be moderate and winter cold stress due to low air and soil temperatures appeared to have an influence on plant water balance through their effects on flow resistances. Abbreviations.&quot; g ..... stomatal conductance; g ....... maximum stomatal conductance, PAR, photosyntheti- cally active radiation; RH, relative humidity of the air; T, leaf transpiration; Ta, air temperature; TL, leaf temperature; T ........ maximum leaf transpiration; AW, air-to-leaf vapor pressure difference; W, shoot water potential; tIJPD, predawn shoot water potential; ttJMIN, minimum shoot water potential.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Oliveira, G</style></author><author><style face="normal" font="default" size="100%">Correia, O A</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Water relations of crok-oak (Quercus suber L.) under natural conditions</style></title><secondary-title><style face="normal" font="default" size="100%">Plant Ecology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Mediterranean climate</style></keyword><keyword><style  face="normal" font="default" size="100%">montado</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber</style></keyword><keyword><style  face="normal" font="default" size="100%">soil-to-leaf hydraulic conductivity</style></keyword><keyword><style  face="normal" font="default" size="100%">Stomatal conductance</style></keyword><keyword><style  face="normal" font="default" size="100%">Transpiration</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1992</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1992///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.springerlink.com/index/v1675t7354l52260.pdf</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">99-100</style></volume><pages><style face="normal" font="default" size="100%">199 - 208</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Daily and annual courses of leaf transpiration, stomatal conductance and shoot water potential of four Quercus suber individuals were compared in a semi-natural stand in southwest Portugal, from spring 1989 to early summer 1990. The trees investigated showed annual patterns typical of evergreen sclerophyllous species but varied in their range of stomatal operation. This appeared to be related to differences in hydraulic conductiv- ity in the root-to-leaf pathway. Maximum stomatal conductance and transpiration rates occurred from March to June. Water stress was found to be moderate and winter cold stress due to low air and soil temperatures appeared to have an influence on plant water balance through their effects on flow resistances. Abbreviations.&quot; g ..... stomatal conductance; g ....... maximum stomatal conductance, PAR, photosyntheti- cally active radiation; RH, relative humidity of the air; T, leaf transpiration; Ta, air temperature; TL, leaf temperature; T ........ maximum leaf transpiration; AW, air-to-leaf vapor pressure difference; W, shoot water potential; tIJPD, predawn shoot water potential; ttJMIN, minimum shoot water potential.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>3</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Correia, O A</style></author><author><style face="normal" font="default" size="100%">Oliveira, G</style></author><author><style face="normal" font="default" size="100%">Martins-Loução, M a</style></author><author><style face="normal" font="default" size="100%">Catarino, F M</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Aspectos fisiológicos do descortiçamento em Querqus suber</style></title><secondary-title><style face="normal" font="default" size="100%">I Congresso Ibérico de Ciências Hortícolas, 18 a 21 de Junho de 1990 em Lisboa</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Descortiçamento</style></keyword><keyword><style  face="normal" font="default" size="100%">Fisiologia vegetal</style></keyword><keyword><style  face="normal" font="default" size="100%">Sobreiro (Quercus Suber L.)</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1990</style></year></dates><pages><style face="normal" font="default" size="100%">469-475</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Quercus suber is the primary source of industrial cork, and can produce cork every 9-10 years. The main objective of the present work was to investigate the influence of the bark stripping of the cork-oak on the stomacal activity and water relations. For this purpose, diurnal variations on transpiration, stomacal conductance and water potencial were studied before and after bark stripping during July and August 1989. The stripping on the trees had been done at various levels. The water loss by the stripping surface was also measured. These preliminary results show that the stress caused by stripping on these trees is different according to the stripping area. The transpiration is immediatly reduced after stripping, under the conditions of these investigations and high stripping coeficients. Sendo o sobreiro uma espécie que proporciona sucessivas tiradas de cortiça, um dos aspectos que importa salientar é o dos exagerados descortiçamentos, que poderão ser um factor de decréscimo de produtividade. Neste trabalho foi estudada a reacção de plantas submetidas a diferentes coeficientes de descortiçamento no que respeita aos parâmetros fisiológicos relacionados com o balanço hídrico e economia de água. Foram efectuados estudos ecofisiológicos em árvores descortiçadas nos meses de Julho 89/Agosto 89, tendo sido estudada a variação diurna da transpiração, condutância estomática e condutividade hidráulica. Foi igualmente determinada a perda de água, por evaporação, através do tronco até à formação de nova periderme. São apresentados resultados preliminares que põem em evidência o stress que o descortiçamento provoca nestas plantas e que é tanto mais grave quanto maior for o coeficiente de descortiçamento aplicado.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>47</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Correia, O A</style></author><author><style face="normal" font="default" size="100%">Oliveira, G</style></author><author><style face="normal" font="default" size="100%">Martins-Loução, M a</style></author><author><style face="normal" font="default" size="100%">Catarino, F M</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Aspectos fisiológicos do descortiçamento em Querqus suber</style></title><secondary-title><style face="normal" font="default" size="100%">I Congresso Ibérico de Ciências Hortícolas, 18 a 21 de Junho de 1990 em Lisboa</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Descortiçamento</style></keyword><keyword><style  face="normal" font="default" size="100%">Fisiologia vegetal</style></keyword><keyword><style  face="normal" font="default" size="100%">Sobreiro (Quercus Suber L.)</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1990</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1990</style></date></pub-dates></dates><pages><style face="normal" font="default" size="100%">469 - 475</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Quercus suber is the primary source of industrial cork, and can produce cork every 9-10 years. The main objective of the present work was to investigate the influence of the bark stripping of the cork-oak on the stomacal activity and water relations. For this purpose, diurnal variations on transpiration, stomacal conductance and water potencial were studied before and after bark stripping during July and August 1989. The stripping on the trees had been done at various levels. The water loss by the stripping surface was also measured. These preliminary results show that the stress caused by stripping on these trees is different according to the stripping area. The transpiration is immediatly reduced after stripping, under the conditions of these investigations and high stripping coeficients. Sendo o sobreiro uma espécie que proporciona sucessivas tiradas de cortiça, um dos aspectos que importa salientar é o dos exagerados descortiçamentos, que poderão ser um factor de decréscimo de produtividade. Neste trabalho foi estudada a reacção de plantas submetidas a diferentes coeficientes de descortiçamento no que respeita aos parâmetros fisiológicos relacionados com o balanço hídrico e economia de água. Foram efectuados estudos ecofisiológicos em árvores descortiçadas nos meses de Julho 89/Agosto 89, tendo sido estudada a variação diurna da transpiração, condutância estomática e condutividade hidráulica. Foi igualmente determinada a perda de água, por evaporação, através do tronco até à formação de nova periderme. São apresentados resultados preliminares que põem em evidência o stress que o descortiçamento provoca nestas plantas e que é tanto mais grave quanto maior for o coeficiente de descortiçamento aplicado.</style></abstract></record></records></xml>