<?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%">Gouveia, António C.</style></author><author><style face="normal" font="default" size="100%">Freitas, Helena</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Modulation of leaf attributes and water use efficiency in Quercus suber along a rainfall gradient</style></title><secondary-title><style face="normal" font="default" size="100%">Trees</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">carbon isotope discrimination</style></keyword><keyword><style  face="normal" font="default" size="100%">carbon isotope discrimination á</style></keyword><keyword><style  face="normal" font="default" size="100%">evergreen tree</style></keyword><keyword><style  face="normal" font="default" size="100%">evergreen tree á</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf plasticity</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf plasticity á</style></keyword><keyword><style  face="normal" font="default" size="100%">rainfall gradient</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2008</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2008///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.springerlink.com/index/10.1007/s00468-008-0274-zhttp://link.springer.com/10.1007/s00468-008-0274-z</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">23</style></volume><pages><style face="normal" font="default" size="100%">267 - 275</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The aim of our study was to assess the intraspeciﬁc variation of a range of leaf attributes and carbon isotope discrimination (D), in Quercus suber, along an 800 mm rainfall gradient in Portugal. We measured speciﬁc leaf area (SLA), leaf thickness (LT) and density, and used leaf carbon isotope content as an integrated record of water use efﬁciency. The values of SLA of Q. suber were strongly, positively correlated with rainfall, decreasing as rainfall decreased. This reduction was mainly driven by LT, which was tightly correlated with SLA (R = -0.80, P\0.001), and steadily increased with declining rainfall. The signiﬁcant increase in carbon isotope discrimination towards the wetter end of the gradient, with a difference of 4.2% in D between the two extremes, suggests a strong adjustment of leaf gas exchange to water availability. Leaf changes associated with precipitation in Q. suber thus seem to inﬂuence water economy, since reduction of SLA with the increase of LT with aridity improves water use efﬁ- ciency. These data suggest that this evergreen tree species relies on its foliage plasticity and physiology to overcome water shortage.</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%">Ceballos, Antonio</style></author><author><style face="normal" font="default" size="100%">Martı́nez-Fernández, José</style></author><author><style face="normal" font="default" size="100%">Luengo-Ugidos, Miguel Ángel</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Analysis of rainfall trends and dry periods on a pluviometric gradient representative of Mediterranean climate in the Duero Basin, Spain</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Arid Environments</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">dry spells</style></keyword><keyword><style  face="normal" font="default" size="100%">duero basin</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean ecosystems</style></keyword><keyword><style  face="normal" font="default" size="100%">rainfall gradient</style></keyword><keyword><style  face="normal" font="default" size="100%">rainfall variability</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/S0140196303001307</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">58</style></volume><pages><style face="normal" font="default" size="100%">215 - 233</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The present work studies the trends in rainfall and the behaviour of dry spells along a pluviometric gradient representative of the conditions of the Mediterranean region. The region is characterized by a marked water deﬁcit in the summer, a pronounced irregularity in its rainfall regime, and a noteworthy frequency of dry spells or periods without appreciable rainfall. The results obtained conﬁrm the general previsions of the IPCC, with a predominance of dry years over wet ones and a negative rainfall trend in the central sector. An increase in intra-annual variability in rainfall, and a very pronounced occurrence of dry periods independent of the total annual rainfall, are also seen. These circumstances will potentially increase the vulnerability of several Mediterranean ecosystems located along the gradient that are currently subject to considerable pressure from human activities; this will increase the environmental problems of these zones (agro-forestry–grazing productivity, soil degradation, recharge of aquifers, forest ﬁres, runoff models, biological diversity and composition, etc.).</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue></record></records></xml>