<?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%">Quero, JoséL.</style></author><author><style face="normal" font="default" size="100%">Sterck, FrankJ.</style></author><author><style face="normal" font="default" size="100%">Martínez-Vilalta, Jordi</style></author><author><style face="normal" font="default" size="100%">Villar, Rafael</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Water-use strategies of six co-existing Mediterranean woody species during a summer drought</style></title><secondary-title><style face="normal" font="default" size="100%">Oecologia</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Anisohydric</style></keyword><keyword><style  face="normal" font="default" size="100%">embolism</style></keyword><keyword><style  face="normal" font="default" size="100%">Isohydric</style></keyword><keyword><style  face="normal" font="default" size="100%">photosynthesis</style></keyword><keyword><style  face="normal" font="default" size="100%">Stomatal conductance</style></keyword><keyword><style  face="normal" font="default" size="100%">water potential</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2011</style></year></dates><publisher><style face="normal" font="default" size="100%">Springer-Verlag</style></publisher><volume><style face="normal" font="default" size="100%">166</style></volume><pages><style face="normal" font="default" size="100%">45-57</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Drought stress is known to limit plant performance in Mediterranean-type ecosystems. We have investigated the dynamics of the hydraulics, gas exchange and morphology of six co-existing Mediterranean woody species growing under natural ﬁeld conditions during a drought that continued during the entire summer. Based on the observed minimum leaf water potentials, our results suggest that the six co-existing species cover a range of plant hydraulic strategies, from isohydric to anisohydric. These differences are remarkable since the selected individuals grow within several meters of each other, sharing the same environment. Surprisingly, whatever the leaf water potentials were at the end of the dry period, stomatal conductance, photosynthesis and transpiration rates were relatively similar and low across species. This result contradicts the classic view that anisohydric species are able to maintain gas exchange for longer periods of time during drought stress. None of the plants showed the expected structural acclimation response to the increasing drought (reduction of leaf-to-sapwood area ratio), thereby rejecting the functional equilibrium hypothesis for our study system. Instead, three of the six species increased photosynthetic area at the branch level. The observed dissimilar patterns of gas exchange, hydraulics and morphology across species seem to be equally successful given that photosynthesis at the leaf level was maintained at similar rates over the whole dry period.</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%">Tognetti, R</style></author><author><style face="normal" font="default" size="100%">Giovannelli, A</style></author><author><style face="normal" font="default" size="100%">Longobucco, A</style></author><author><style face="normal" font="default" size="100%">Miglietta, F</style></author><author><style face="normal" font="default" size="100%">Raschi, A</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Water relations of oak species growing in the natural CO2 spring of Rapolano (central Italy)</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%">Drought</style></keyword><keyword><style  face="normal" font="default" size="100%">Elevated CO2</style></keyword><keyword><style  face="normal" font="default" size="100%">embolism</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus pubescens</style></keyword><keyword><style  face="normal" font="default" size="100%">sap flow</style></keyword><keyword><style  face="normal" font="default" size="100%">water relations</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%">475-485</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The effect of elevated atmospheric carbon dioxide on water relations was examined on downy oak (Quercus pubescens) and holm oak (Q ilex) trees. The study was conducted on trees growing in a naturally enriched CO2 spring. Sap velocity and sap flow were measured by the heat pulse technique. On the same trees, daily courses of xylem water potential, leaf conductance and transpiration were monitored. Plant water relations were evaluated by pressure-volume analysis method on shoots; on the same branches, relative conductivity of xylem was measured. Both species exhibited increased osmotic potential and decreased symplasmic fraction of water in trees adapted to increased CO2. Downy oak showed lower stomatal conductance under elevated CO2, but holm oak did not. Both species displayed higher sap flow in control trees. In both species, increased carbon dioxide did not influence xylem embolism formation.</style></abstract></record></records></xml>