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Ecophysiology axis

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Ecophysiology of tree responses to water deficit

 

L. Beaudonnat, F. Brignolas, D. Chassagnaud, M. Feinard-Duranceau, R. Fichot*, I. Le Jan, C. Vincent-Barbaroux

 

* contact : regis.fichot@univ-orleans.fr

Aims & strategy
We aim at better understanding the diversity of tree physiological responses to water deficit in a context of global change. Physiological responses are approached through the prism of (i) water relations (water transport and hydraulic dysfunction, stomatal regulation, xylem functional anatomy, etc…) and (ii) carbon sink-source relationships (photosynthesis, growth dynamics, allocation, carbon reserves, etc…). We conduct experiments under controlled conditions (growth chambers, greenhouse), semi-controlled conditions (field nurseries and common gardens), or natural conditions (riparian forest, plain forest) to account for multiple drought contexts (rapid vs. long lasting, moderate vs. lethal). We have a long-standing record on tree physiological responses to water deficit, but our current efforts are directed towards:

  1. Identifying the suites of traits involved in acclimation or resilience/mortality and associated physiological thresholds.
  2. Assessing to what extent recurrent droughts affect subsequent responses through priming (see also the Axis Epigenetics).
  3. Understanding how and to what extent other interacting abiotic factors such as nutrient status can shape response trajectories and favour resilience or in contrast act as predisposing factors.

Poplar remains the main biological model for practical, physiological, ecological and economic reasons with the aim of understanding genetic variations in drought tolerance in relation to population evolutionary histories (local adaptation) or for tree breeding and the selection of ideotypes.
We translate our expertise to other tree species depending on project opportunities and questions addressed. In this context, we develop remote sensing approaches with the aim of bridging gaps between fine-scale tree physiology and large-scale processes such as forest die-offs and mortality, especially in oak and pine forests.
 

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scales, processes, related traits and methods to study tree physiological responses to water deficit

Figure 1: scales, processes, related traits and methods to study tree physiological responses to water deficit

 

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