Additive effects of high growth rate and low transpiration rate drive differences in whole plant transpiration efficiency among black poplar genotypes

Marie-Béatrice Bogeat-Triboulot (1) , Cyril Buré (1) , Théo Gerardin (1) , Pierre-Antoine Chuste (1) , Didier Le Thiec (1) , Irène Hummel (1) , Maxime Durand (1) , H. Wildhagen (2) , C. Douthe (3) , A. Molins (3) , J. Galmés (3) , H.K. Smith (4) , J. Flexas (3) , A. Polle (2) , G. Taylor (4, 5) , Oliver Brendel (1)

1 SILVA - SILVA
2 Forest Botany and Tree Physiology
3 Instituto de investigaciones Agroambientales y de Economía del Agua (INAGEA)
4 University of Sydney - Biological Sciences
5 Department of Plant Sciences

Poplar plantations, widely used for the production of woody biomass, might be at high risk from the climate change-induced increase in the frequency of drought periods. Therefore, selecting improved genotypes, which are highly productive but with a high water use efficiency (WUE), is becoming a major target. The use of automated weighing systems in controlled environments facilitates the estimation of cumulated water loss and whole plant transpiration efficiency (TE). Differences in TE and leaf level intrinsic WUE as well as the contribution of underlying ecophysiological traits were determined in three contrasting P. nigra genotypes. Strong differences in TE among the selected genotypes were congruent with differences in leaf level intrinsic WUE. Our data show that a high total leaf area was overcompensated by a low per leaf area transpiration rate, leading to higher TE in highly productive genotypes originating from cool locations. Nocturnal water loss was relatively low but contributed to variations in TE among genotypes. In response to drought, leaf level WUE increased but not TE, suggesting that carbon losses due to whole plant respiration could offset the drought-induced increase in intrinsic WUE.

Mots clés: Nocturnal Transpiration; Transpiration Efficiency; black poplar; Water Use Efficiency; Intraspecific Diversity; Poplar; Water Deficit

Mots clés: populus; efficience d'utilisation de l'eau; comparaison de génotypes; populus nigra; arbre; adaptation à la sécheresse; transpiration végétale

Domaines: Sciences du Vivant [q-bio]

Marie-Béatrice Bogeat-Triboulot, Cyril Buré, Théo Gerardin, Pierre-Antoine Chuste, Didier Le Thiec, et al.. Additive effects of high growth rate and low transpiration rate drive differences in whole plant transpiration efficiency among black poplar genotypes. Environmental and Experimental Botany, 2019, 166, pp.1-11. ⟨10.1016/j.envexpbot.2019.05.021⟩. ⟨hal-02264373⟩