<?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%">Gullo, M A Lo</style></author><author><style face="normal" font="default" size="100%">Salleo, S</style></author><author><style face="normal" font="default" size="100%">Rosso, R</style></author><author><style face="normal" font="default" size="100%">Trifilo, P</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Drought resistance of 2-year-old saplings of Mediterranean forest trees in the field: relations between water relations, hydraulics and productivity</style></title><secondary-title><style face="normal" font="default" size="100%">Plant and soil</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">cavitation</style></keyword><keyword><style  face="normal" font="default" size="100%">Drought resistance</style></keyword><keyword><style  face="normal" font="default" size="100%">hydraulics</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean trees</style></keyword><keyword><style  face="normal" font="default" size="100%">Reforestation</style></keyword><keyword><style  face="normal" font="default" size="100%">water relations</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2003</style></year></dates><volume><style face="normal" font="default" size="100%">250</style></volume><pages><style face="normal" font="default" size="100%">259-272</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Drought resistance was examined for 2-year-old saplings of Ceratonia siliqua L., Olea oleaster Hoffmgg. et Link., Quercus suber L. and Q. pubescens Willd. growing in the ﬁeld in Sicily, with the aim of testing their possible use in the reforestation of degraded areas. To this purpose, leaf conductance to water vapour (gL), transpiration rate (EL), relative water content (RWC) and water potential (L) were measured between pre-dawn and sunset, monthly from May to November. Parallel measurements of loss of hydraulic conductance of twigs of the current year (PLC) were made together with an estimate of whole-plant hydraulic conductance (KPLANT) on the basis of the ratio of maximum EL to (PD − MIN), where PD is pre-dawn L and MIN is the minimum diurnal L. C. siliqua saplings maintained high gL throughout the study period with high RWC (over 90%) and L. They grew rapidly and increased their foliage area (AL) by over 60% from May to winter rest. This was accompanied by low twig PLC (about 20% in September) resulting in high KPLANT all through the study period. In contrast, O. oleaster saplings underwent distinct dehydration in July, i.e. they showed stomatal closure due to a drop in RWC (to 75%) and L (to the turgor-loss point). This was apparently due to twig cavitation, resulting in a strong decrease of KPLANT. Plants, however, tolerated summer drought, and showed growth (AL increased by 15% from May to November). Saplings of Q. suber and Q. pubescens were much more vulnerable to twig cavitation (PLC was 35–48% from June to November) than the other two species, and their average KPLANT was lower. Saplings of Q. suber and Q. pubescens grew only during the wet spring period, and no new foliage was produced thereafter. Changes in twig hydraulic conductance played a dominant role in determining changes in KPLANT in that the two variables were well correlated to each other (r = 0.68 for P = 0.001). We conclude that C. siliqua is an ideal candidate for reforestation of Sicilian degraded areas as is O. oleaster that, however, requires some additional water supply in the summer, at least during the early years after plantation. In wetter locations of Sicily, to an altitude between 0 and 500 m, Q. suber and Q. pubescens can be used for reforestation with expected higher competitiveness of the latter over the former species.</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%">Salleo, S</style></author><author><style face="normal" font="default" size="100%">GULLO, M A L O</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Sclerophylly and Plant Water Relations in Three Mediterranean Quercus Species</style></title><secondary-title><style face="normal" font="default" size="100%">Annals of Botany</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Drought resistance</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf conductance</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus pubescens (PG)</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber L.</style></keyword><keyword><style  face="normal" font="default" size="100%">Relative water content</style></keyword><keyword><style  face="normal" font="default" size="100%">sclerophylly</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1990</style></year></dates><volume><style face="normal" font="default" size="100%">65</style></volume><pages><style face="normal" font="default" size="100%">259-270</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The possible role in drought resistance played by sclerophylly was studied in the Mediterranean oaks Quercus ilex, Q. suber and Q. pubescens. Studies were conducted on leaves at 30, 50 and 80% of their final surface area, as well as on mature leaves of the current year's growth in June and September and on 1-year-old leaves.Leaves of different ages of the three species showed quite different degrees of sclerophylly (DS). Q. ilex leaves reached the definitive DS of 1.75 g dm−2 during leaf expansion; Q. pubescens leaves hardened at the end of their expansion, with a final DS of 0.93 g dm−2; Q. suber showed the lowest DS of 0.76 g dm−2.Leaf conductance to water vapour (g1) of 1-year-old leaves of Q. ilex, measured in the field, showed a duration of the g1 peak values about twice that of the other two species. The minimum leaf relative water content (RWC), however, was near the same in the three species, indicating that water loss was recovered partly by Q. ilex leaves. This was apparently due to the higher bulk modulus of elasticity (max) as resulting from leaf water potential isotherms.High correlation coefficients were noted between DS and max but large changes in DS were needed to display minor changes in max. When both DS and max were correlated to the minimum RWC, an increase in DS of 133 % (corresponding to an increase in max of only 12 %) was needed to cause an increase in RWC of 2%. Therefore, sclerophylly cannot be considered as significantly related to a drought-avoiding strategy.</style></abstract></record></records></xml>