Diversity of water use efficiency among Quercus robur genotypes: contribution of related leaf traits | Diversité de l’efficience d’utilisation de l’eau entre différents génotypes de Quercus robur : contributions des traits foliaires
2009
Roussel, Magali | Le Thiec, Didier | Montpied, Pierre | Ningre, Nathalie | Guehl, Jean-Marc | Brendel, Oliver
• Previously, a large intra-specific diversity and a tight genetic control have been shown for Δ¹³C (carbon isotope discrimination) in a pedunculate oak (Quercus robur L.) family, which is an estimator for intrinsic water use efficiency (Wᵢ), a complex trait defined as the ratio of net CO₂assimilation rate (A) to stomatal conductance for water vapour (g ₛ). • In the present study, twelve genotypes with extreme phenotypic values of Δ¹³C were selected within this family to (i) asses the stability of genotype differences across contrasting environments and for different measures Wᵢ; (ii) quantify the relationship between Δ¹³C and Wᵢwithin this family; (iii) identify which leaf traits drive the diversity in Wᵢobserved in this family. • Genetic variability of Δ¹³C and Wᵢwas largely independent from different temporal integration scales and their correlation was found to be strong (R²= 88% for leaf sugars) within this family. • Weak correlations between measures of Wᵢwith estimators of photosynthetic capacity, suggest a minor role of the latter in the diversity of Wᵢ. • However, the tight correlation between gₛand Δ¹³C as well as Wᵢ, and the related genotypic variation in stomatal density, suggest that the genotypic diversity in Wᵢwithin this pedunculate oak family might be due to differences in g ₛ .
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