title: Genetic variation for leaf morphology, leaf structure and leaf carbon isotope discrimination in European populations of black poplar (Populus nigra L.).
abstract: To buffer against the high spatial and temporal heterogeneity of the riparian habitat, riparian tree species, such as black poplar (Populus nigra L.), may display a high level of genetic variation and phenotypic plasticity for functional traits. Using a multisite common garden experiment, we estimated the relative contribution of genetic and environmental effects on the phenotypic variation expressed for individual leaf area, leaf shape, leaf structure and leaf carbon isotope discrimination (Δ(13)C) in natural populations of black poplar. Twenty-four to 62 genotypes were sampled in nine metapopulations covering a latitudinal range from 48 °N to 42 °N in France and in Italy and grown in two common gardens at Orléans (ORL) and at Savigliano (SAV). In the two common gardens, substantial genetic variation was expressed for leaf traits within all metapopulations, but its expression was modulated by the environment, as attested by the genotype × environment (G × E) interaction variance being comparable to or even greater than genetic effects. For LA, G × E interactions were explained by both changes in genotype ranking between common gardens and increased variation in SAV, while these interactions were mainly attributed to changes in genotype ranking for Δ(13)C. The nine P. nigra metapopulations were highly differentiated for LA, as attested by the high coefficient of genetic differentiation (QST = 0.50 at ORL and 0.51 at SAV), and the pattern of metapopulation differentiation was highly conserved between the two common gardens. In contrast, they were moderately differentiated for Δ(13)C (QST = 0.24 at ORL and 0.25 at SAV) and the metapopulation clustering changed significantly between common gardens. Our results evidenced that the nine P. nigra metapopulations present substantial genetic variation and phenotypic plasticity for leaf traits, which both represent potentially significant determinants of populations' capacities to respond, on a short-term basis and over generations, to environmental variations.
authors.affiliation: Université d'Orléans, INRA, EA 1207, Laboratoire de Biologie des Ligneux et des Grandes Cultures, F-45067 Orléans, France INRA, UR 0588 'Amélioration, Génétique et Physiologie Forestières' (AGPF), Centre de recherche Val de Loire, CS 40001 Ardon, F-45075 Orléans Cedex 2, France.
authors.forename: Justine
authors.initials: J
authors.lastname: Guet
authors.affiliation: Department for Innovation in Biological, Agro-food and Forest systems, University of Tuscia, Via S. Camillo de Lellis, 01100 Viterbo, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Fabbrini
authors.affiliation: Université d'Orléans, INRA, EA 1207, Laboratoire de Biologie des Ligneux et des Grandes Cultures, F-45067 Orléans, France.
authors.forename: Régis
authors.initials: R
authors.lastname: Fichot
authors.affiliation: Department for Innovation in Biological, Agro-food and Forest systems, University of Tuscia, Via S. Camillo de Lellis, 01100 Viterbo, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Sabatti
authors.affiliation: INRA, UR 0588 'Amélioration, Génétique et Physiologie Forestières' (AGPF), Centre de recherche Val de Loire, CS 40001 Ardon, F-45075 Orléans Cedex 2, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Bastien
authors.affiliation: Université d'Orléans, INRA, EA 1207, Laboratoire de Biologie des Ligneux et des Grandes Cultures, F-45067 Orléans, France franck.brignolas@univ-orleans.fr.
authors.forename: Franck
authors.initials: F
authors.lastname: Brignolas
mesh_terms: D002247:Carbon Isotopes / Q000032:analysis; D002980:Climate; D004777:Environment; D014644:Genetic Variation; D005838:Genotype; D010641:Phenotype; D018515:Plant Leaves / Q000033:anatomy & histology / Q000235:genetics* / Q000502:physiology; D032107:Populus / Q000033:anatomy & histology / Q000235:genetics* / Q000502:physiology; D014197:Trees; D014867:Water / Q000378:metabolism
chemical_list: D002247:Carbon Isotopes; D014867:Water
keywords: bulk leaf carbon isotope discrimination; common gardens; leaf traits; natural populations; phenotypic plasticity; population differentiation