Le contexte de changement de climat incite la recherche à identifier de nouveaux critères de sélection pour la populiculture de demain. L’efficience d’utilisation de l’eau, la capacité à maintenir ...une croissance en cas de sécheresse modérée et la résistance à la cavitation sont des caractères très variables entre cultivars et indépendants de leur niveau de productivité. Ils pourraient donc être utilisés pour la sélection de cultivars capables de mieux résister à la sécheresse.
Le contexte de changement de climat incite la recherche à identifier de nouveaux critères de sélection pour la populiculture de demain. L’efficience d’utilisation de l’eau, la capacité à maintenir ...une croissance en cas de sécheresse modérée et la résistance à la cavitation sont des caractères très variables entre cultivars et indépendants de leur niveau de productivité. Ils pourraient donc être utilisés pour la sélection de cultivars capables de mieux résister à la sécheresse.
Xylem resistance to drought-induced cavitation is a key trait of plant water relations. This study assesses the genetic variation expressed for stem cavitation resistance within a population of a ...riparian species, the European black poplar (Populus nigra L.), and explores its relationships with xylem anatomy, water-use efficiency (WUE), and growth. Sixteen structural and physiological traits related to cavitation resistance, xylem anatomy, growth, bud phenology, and WUE were measured on 33 P. nigra genotypes grown under optimal irrigation in a 2-year-old clonal experiment in a nursery. Significant genetic variation was expressed for the xylem tension inducing 50% loss of hydraulic conductivity (Ψ50) within the studied population, as attested by the high value of broad-sense heritability estimated for this trait (H 2 ind = 0.72). Stem cavitation resistance was associated with xylem structure: the more cavitation-resistant genotypes exhibited lower hydraulic efficiency and higher mechanical reinforcement as assessed from stem xylem cross sections. By contrast, Ψ50 was not significantly related to shoot height increment, total above-ground dry mass, or bulk leaf carbon isotope discrimination, a proxy for intrinsic WUE. These findings indicate that the trade-offs between xylem resistance to cavitation, hydraulic efficiency, and mechanical reinforcement can occur at the within-population level. Given that the studied genotypes were exposed to the same environmental conditions and evolutionary drivers in situ, the trade-offs detected at this scale are expected to reflect true functional relationships.
Xylem resistance to drought-induced cavitation is a key trait of plant water relations. This study assesses the genetic variation expressed for stem cavitation resistance within a population of a ...riparian species, the European black poplar (Populus nigra L.), and explores its relationships with xylem anatomy, water-use efficiency (WUE), and growth. Sixteen structural and physiological traits related to cavitation resistance, xylem anatomy, growth, bud phenology, and WUE were measured on 33 P. nigra genotypes grown under optimal irrigation in a 2-year-old clonal experiment in a nursery. Significant genetic variation was expressed for the xylem tension inducing 50% loss of hydraulic conductivity (Ψ50) within the studied population, as attested by the high value of broad-sense heritability estimated for this trait (H 2 ind = 0.72). Stem cavitation resistance was associated with xylem structure: the more cavitation-resistant genotypes exhibited lower hydraulic efficiency and higher mechanical reinforcement as assessed from stem xylem cross sections. By contrast, Ψ50 was not significantly related to shoot height increment, total above-ground dry mass, or bulk leaf carbon isotope discrimination, a proxy for intrinsic WUE. These findings indicate that the trade-offs between xylem resistance to cavitation, hydraulic efficiency, and mechanical reinforcement can occur at the within-population level. Given that the studied genotypes were exposed to the same environmental conditions and evolutionary drivers in situ, the trade-offs detected at this scale are expected to reflect true functional relationships.
The ongoing global change could be an additional threat to the establishment and the long-term survival of Populus nigra L., an emblematic European riparian species. With the general aim of gaining ...insights into the adaptive potential of this species, we (i) quantified variations within and among three French P. nigra populations for key physiological attributes, i.e., water-use efficiency (assessed from bulk leaf carbon isotope discrimination, Δ13C), growth performance and related leaf traits, (ii) examined genotype and population by environment interactions, and (iii) explored the relationship between Δ13C and growth. Thirty genotypes were sampled in each of three naturally established populations and grown in two different sites, Orléans (ORL) and Guémené-Penfao (GMN). In ORL, two similar plots were established and different watering regimes were applied in order to test for the drought response. Significant variations were observed for all traits within and among populations irrespective of site and watering. Trait variation was larger within than among populations. The effect of drought was neither genotype- nor population-dependent, contrary to the effect of site. The population ranking was maintained in all sites and watering regimes for the two most complex traits: Δ13C and growth. Moreover, these two traits were unrelated, which indicates that (i) water-use efficiency and growth are largely uncoupled in this species, and (ii) the environmental factors driving genetic structuration for Δ13C and growth act independently. The large variations found within populations combined with the consistent differences among populations suggest a large adaptive potential for P. nigra.
The ongoing global change could be an additional threat to the establishment and the long-term survival of Populus nigra L., an emblematic European riparian species. With the general aim of gaining ...insights into the adaptive potential of this species, we (i) quantified variations within and among three French P. nigra populations for key physiological attributes, i.e., water-use efficiency (assessed from bulk leaf carbon isotope discrimination, Δ13C), growth performance and related leaf traits, (ii) examined genotype and population by environment interactions, and (iii) explored the relationship between Δ13C and growth. Thirty genotypes were sampled in each of three naturally established populations and grown in two different sites, Orléans (ORL) and Guémené-Penfao (GMN). In ORL, two similar plots were established and different watering regimes were applied in order to test for the drought response. Significant variations were observed for all traits within and among populations irrespective of site and watering. Trait variation was larger within than among populations. The effect of drought was neither genotype- nor population-dependent, contrary to the effect of site. The population ranking was maintained in all sites and watering regimes for the two most complex traits: Δ13C and growth. Moreover, these two traits were unrelated, which indicates that (i) water-use efficiency and growth are largely uncoupled in this species, and (ii) the environmental factors driving genetic structuration for Δ13C and growth act independently. The large variations found within populations combined with the consistent differences among populations suggest a large adaptive potential for P. nigra.
Survivorship in potted Populus deltoides x Populus nigra hybrids in response to gradual soil water depletion Barigah , Tete Severien (INRA , Clermont-Ferrand (France). UMR 0547 Physique et Physiologie Intégratives de l'Arbre Fruitier et Forestier); Douris , Marie (INRA , Clermont-Ferrand (France). UMR 0547 Physique et Physiologie Intégratives de l'Arbre Fruitier et Forestier); Bonhomme , Marc (INRA , Clermont-Ferrand (France). UMR 0547 Physique et Physiologie Intégratives de l'Arbre Fruitier et Forestier) ...
2011
Conference Proceeding
