1. Photosynthetic sensitivity to drought varies among populations of Quercus ilex along a rainfall gradient
- Author
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Julien Ruffault, Serge Rambal, Laurent Misson, Jesús Rodríguez-Calcerrada, Matthew G. Letts, Jean-Marc Limousin, Nicolas Martin-StPaul, Centre d’Ecologie Fonctionnelle et Evolutive (CEFE), Université Paul-Valéry - Montpellier 3 (UPVM)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Department of Biology [New Mexico], The University of New Mexico [Albuquerque], Department of Geography, University of Lethbridge, ANR-06-VULN-003-01, Additional support was provided by the European project CARBOEXTREME (EP7-ENV-2008-1, project number 226701), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Université Paul-Valéry - Montpellier 3 (UPVM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut de Recherche pour le Développement (IRD [France-Sud]), and Martin-StPaul, Nicolas
- Subjects
0106 biological sciences ,Ecophysiology ,Mediterranean climate ,Farquhar model ,[SDV.SA]Life Sciences [q-bio]/Agricultural sciences ,Stomatal conductance ,Population ,carbon sequestration ,ecohydrological equilibrium theory ,evergreen forest ,holm oak ,hydraulic architecture ,leaf gas exchange ,precipitation gradient ,Plant Science ,Biology ,Photosynthesis ,01 natural sciences ,03 medical and health sciences ,Botany ,conductance stomatique ,Leaf area index ,quercus ilex ,education ,030304 developmental biology ,écosystème forestier ,0303 health sciences ,education.field_of_study ,AMAX ,sensibilité à la sécheresse ,15. Life on land ,Photosynthetic capacity ,Agricultural sciences ,taux de carboxylation ,séquestration du carbone ,Agronomy ,13. Climate action ,capacité photosynthétique ,Agronomy and Crop Science ,Sciences agricoles ,010606 plant biology & botany - Abstract
International audience; Drought frequency and intensity are expected to increase in the Mediterranean as a consequence of global climate change. To understand how photosynthetic capacity responds to long-term water stress, we measured seasonal patterns of stomatal (S-L), mesophyll (MCL) and biochemical limitations (B-L) to net photosynthesis (A(max)) in three Quercus ilex (L.) populations from sites differing in annual rainfall. In the absence of water stress, stomatal conductance (g(s)), maximum carboxylation capacity (V-cmax), photosynthetic electron transport rate (J(max)) and A(max) were similar among populations. However, as leaf predawn water potential (Psi(l,pd)) declined, the population from the wettest site showed steeper declines in g(s), V-cmax, J(max) and A(max) than those from the drier sites. Consequently, S-L, MCL and B-L increased most steeply in response to decreasing Psi(l,pd) in the population from the wettest site. The higher sensitivity of A(max) to drought was primarily the result of stronger stomatal regulation of water loss. Among-population differences were not observed when g(s) was used instead of Psi(l,pd) as a drought stress indicator. Given that higher growth rates, stature and leaf area index were observed at the wettest site, we speculate that hydraulic architecture may explain the greater drought sensitivity of this population. Collectively, these results highlight the importance of considering among-population differences in photosynthetic responses to seasonal drought in large scale process-based models of forest ecosystem function
- Published
- 2011
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