<?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%">Mediavilla, Sonia</style></author><author><style face="normal" font="default" size="100%">Escudero, Alfonso</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Stomatal responses to drought of mature trees and seedlings of two co-occurring Mediterranean oaks</style></title><secondary-title><style face="normal" font="default" size="100%">Forest Ecology and Management</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Drought</style></keyword><keyword><style  face="normal" font="default" size="100%">growth stages</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf water potential</style></keyword><keyword><style  face="normal" font="default" size="100%">mediterranean quercus species</style></keyword><keyword><style  face="normal" font="default" size="100%">Stomatal conductance</style></keyword><keyword><style  face="normal" font="default" size="100%">vapour pressure deficit</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2004</style></year></dates><volume><style face="normal" font="default" size="100%">187</style></volume><pages><style face="normal" font="default" size="100%">281-294</style></pages><isbn><style face="normal" font="default" size="100%">3423294515</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We studied stomatal responses to decreasing predawn water potential (Cpd ) and increasing leaf-to-air water vapour pressure deﬁcit (VPD) of seedlings and mature trees of two co-occurring Mediterranean oaks with contrasting leaf habits: the evergreen Quercus rotundifolia and the deciduous Quercus faginea. Our objective was to deﬁne and to compare the stomatal strategies of both speciesfordroughtresistanceandtoidentifythepossibledifferencesbetweengrowthstagesinselecteddroughtadaptationattributes. Among the mature trees, Q. rotundifolia exhibited a water-use behaviour that was more conservative than that of Q. faginea: lower maximum stomatal conductances and greater sensitivity to VPD than the deciduous species. As a result, the leaf water potential of the evergreen species never decreased along the day and along the growth season as much as in the deciduous species; this may help to guarantee longer leaf longevity by avoiding irreversible damage during the summer drought. The seedlings of the two species showed a less conservative water-use strategy in comparison with adult trees: a relatively high stomatal conductance and lower stomatal sensitivity to soil and atmospheric drought. As a consequence, leaf water potential decreased more in the seedlings along the day than in the adults. Q. rotundifolia was the species for which the most pronounced differences between growth stages were obtained. Thus, interspeciﬁc differences in response to drought disappeared in the ﬁrst stages of the life of the trees, and the seedlings of the two species showed a common strategy, probably as a response to the competition from the herbaceous layer. A low stomatal sensitivity in beneﬁt of an increase in growth would probably be a more successful strategy under the competitive conditions that seedlings experience during their establishment.</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%">Mediavilla, Sonia</style></author><author><style face="normal" font="default" size="100%">Escudero, Alfonso</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Stomatal responses to drought of mature trees and seedlings of two co-occurring Mediterranean oaks</style></title><secondary-title><style face="normal" font="default" size="100%">Forest Ecology and Management</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Drought</style></keyword><keyword><style  face="normal" font="default" size="100%">growth stages</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf water potential</style></keyword><keyword><style  face="normal" font="default" size="100%">mediterranean quercus species</style></keyword><keyword><style  face="normal" font="default" size="100%">Stomatal conductance</style></keyword><keyword><style  face="normal" font="default" size="100%">vapour pressure deficit</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://linkinghub.elsevier.com/retrieve/pii/S0378112703003827</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">187</style></volume><pages><style face="normal" font="default" size="100%">281 - 294</style></pages><isbn><style face="normal" font="default" size="100%">3423294515</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We studied stomatal responses to decreasing predawn water potential (Cpd ) and increasing leaf-to-air water vapour pressure deﬁcit (VPD) of seedlings and mature trees of two co-occurring Mediterranean oaks with contrasting leaf habits: the evergreen Quercus rotundifolia and the deciduous Quercus faginea. Our objective was to deﬁne and to compare the stomatal strategies of both speciesfordroughtresistanceandtoidentifythepossibledifferencesbetweengrowthstagesinselecteddroughtadaptationattributes. Among the mature trees, Q. rotundifolia exhibited a water-use behaviour that was more conservative than that of Q. faginea: lower maximum stomatal conductances and greater sensitivity to VPD than the deciduous species. As a result, the leaf water potential of the evergreen species never decreased along the day and along the growth season as much as in the deciduous species; this may help to guarantee longer leaf longevity by avoiding irreversible damage during the summer drought. The seedlings of the two species showed a less conservative water-use strategy in comparison with adult trees: a relatively high stomatal conductance and lower stomatal sensitivity to soil and atmospheric drought. As a consequence, leaf water potential decreased more in the seedlings along the day than in the adults. Q. rotundifolia was the species for which the most pronounced differences between growth stages were obtained. Thus, interspeciﬁc differences in response to drought disappeared in the ﬁrst stages of the life of the trees, and the seedlings of the two species showed a common strategy, probably as a response to the competition from the herbaceous layer. A low stomatal sensitivity in beneﬁt of an increase in growth would probably be a more successful strategy under the competitive conditions that seedlings experience during their establishment.</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%">Infante, J M</style></author><author><style face="normal" font="default" size="100%">Rambal, S</style></author><author><style face="normal" font="default" size="100%">Joffre, R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Modelling transpiration in holm-oak savannah: scaling up from the leaf to the tree scale</style></title><secondary-title><style face="normal" font="default" size="100%">Agricultural and Forest Meteorology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">oak savannas</style></keyword><keyword><style  face="normal" font="default" size="100%">seasonal hysteresis</style></keyword><keyword><style  face="normal" font="default" size="100%">southern Spain</style></keyword><keyword><style  face="normal" font="default" size="100%">Transpiration</style></keyword><keyword><style  face="normal" font="default" size="100%">vapour pressure deficit</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1997</style></year></dates><volume><style face="normal" font="default" size="100%">1923</style></volume><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">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</style></abstract></record></records></xml>