<?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%">Vaz, M</style></author><author><style face="normal" font="default" size="100%">Pereira, J S</style></author><author><style face="normal" font="default" size="100%">Gazarini, L C</style></author><author><style face="normal" font="default" size="100%">David, T S</style></author><author><style face="normal" font="default" size="100%">David, J S</style></author><author><style face="normal" font="default" size="100%">Rodrigues, A</style></author><author><style face="normal" font="default" size="100%">MAROCO, J</style></author><author><style face="normal" font="default" size="100%">Chaves, M M</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Drought-induced photosynthetic inhibition and autumn recovery in two Mediterranean oak species (Quercus ilex and Quercus suber)</style></title><secondary-title><style face="normal" font="default" size="100%">Tree Physiology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">biochemical parameters</style></keyword><keyword><style  face="normal" font="default" size="100%">Drought</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean</style></keyword><keyword><style  face="normal" font="default" size="100%">photosynthesis</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber</style></keyword><keyword><style  face="normal" font="default" size="100%">Recovery</style></keyword><keyword><style  face="normal" font="default" size="100%">water relations</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2010</style></year></dates><volume><style face="normal" font="default" size="100%">30</style></volume><pages><style face="normal" font="default" size="100%">946-956</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Responses of leaf water relations and photosynthesis to summer drought and autumn rewetting were studied in two evergreen Mediterranean oak species, Quercus ilex spp. rotundifolia and Quercus suber. The predawn leaf water potential (ΨlPD), stomatal conductance (gs) and photosynthetic rate (A) at ambient conditions were measured seasonally over a 3-year period. We also measured the photosynthetic response to light and to intercellular CO2 (A/PPFD and A/Ci response curves) under water stress (summer) and after recovery due to autumn rainfall. Photosynthetic parameters, Vcmax, Jmax and triose phosphate utilization (TPU) rate, were estimated using the Farquhar model. RuBisCo activity, leaf chlorophyll, leaf nitrogen concentration and leaf carbohydrate concentration were also measured. All measurements were performed in the spring leaves of the current year. In both species, the predawn leaf water potential, stomatal conductance and photosynthetic rate peaked in spring, progressively declined throughout the summer and recovered upon autumn rainfall. During the drought period, Q. ilex maintained a higher predawn leaf water potential and stomatal conductance than Q. suber. During this period, we found that photosynthesis was not only limited by stomatal closure, but was also downregulated as a consequence of a decrease in the maximum carboxylation rate (Vcmax) and the light-saturated rate of photosynthetic electron transport (Jmax) in both species. The Vcmax and Jmax increased after the first autumnal rains and this increase was related to RuBisCo activity, leaf nitrogen concentration and chlorophyll concentration. In addition, an increase in the TPU rate and in soluble leaf sugar concentration was observed in this period. The results obtained indicate a high resilience of the photosynthetic apparatus to summer drought as well as good recovery in the following autumn rains of these evergreen oak species.</style></abstract><notes><style face="normal" font="default" size="100%">10.1093/treephys/tpq044</style></notes><research-notes><style face="normal" font="default" size="100%">10.1093/treephys/tpq044</style></research-notes></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%">Chaves, M M</style></author><author><style face="normal" font="default" size="100%">Pereira, J S</style></author><author><style face="normal" font="default" size="100%">MAROCO, J</style></author><author><style face="normal" font="default" size="100%">RODRIGUES, M L</style></author><author><style face="normal" font="default" size="100%">RICARDO, C P P</style></author><author><style face="normal" font="default" size="100%">OSÓRIO, M L</style></author><author><style face="normal" font="default" size="100%">CARVALHO, I</style></author><author><style face="normal" font="default" size="100%">Faria, T</style></author><author><style face="normal" font="default" size="100%">PINHEIRO, C</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">How Plants Cope with Water Stress in the Field? Photosynthesis and Growth</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%">carbon assimilation</style></keyword><keyword><style  face="normal" font="default" size="100%">high temperature</style></keyword><keyword><style  face="normal" font="default" size="100%">Lupinus</style></keyword><keyword><style  face="normal" font="default" size="100%">photosynthesis</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber</style></keyword><keyword><style  face="normal" font="default" size="100%">stomatal functioning</style></keyword><keyword><style  face="normal" font="default" size="100%">Stress</style></keyword><keyword><style  face="normal" font="default" size="100%">Vitis vinifera</style></keyword><keyword><style  face="normal" font="default" size="100%">water-stress</style></keyword><keyword><style  face="normal" font="default" size="100%">xanthophyll cycle</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2002</style></year></dates><volume><style face="normal" font="default" size="100%">89</style></volume><pages><style face="normal" font="default" size="100%">907-916</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Plants are often subjected to periods of soil and atmospheric water deficit during their life cycle. The frequency of such phenomena is likely to increase in the future even outside today’s arid/semi‐arid regions. Plant responses to water scarcity are complex, involving deleterious and/or adaptive changes, and under field conditions these responses can be synergistically or antagonistically modified by the superimposition of other stresses. This complexity is illustrated using examples of woody and herbaceous species mostly from Mediterranean‐type ecosystems, with strategies ranging from drought‐avoidance, as in winter/spring annuals or in deep‐rooted perennials, to the stress resistance of sclerophylls. Differences among species that can be traced to different capacities for water acquisition, rather than to differences in metabolism at a given water status, are described. Changes in the root : shoot ratio or the temporary accumulation of reserves in the stem are accompanied by alterations in nitrogen and carbon metabolism, the fine regulation of which is still largely unknown. At the leaf level, the dissipation of excitation energy through processes other than photosynthetic C‐metabolism is an important defence mechanism under conditions of water stress and is accompanied by down‐regulation of photochemistry and, in the longer term, of carbon metabolism.</style></abstract><notes><style face="normal" font="default" size="100%">10.1093/aob/mcf105</style></notes><research-notes><style face="normal" font="default" size="100%">10.1093/aob/mcf105</style></research-notes></record></records></xml>