title: Impact of drought on productivity and water use efficiency in 29 genotypes of Populus deltoides x Populus nigra.
abstract: We examined the relationships among productivity, water use efficiency (WUE) and drought tolerance in 29 genotypes of Populus x euramericana (Populus deltoides x Populus nigra), and investigated whether some leaf traits could be used as predictors for productivity, WUE and drought tolerance. At Orléans, France, drought was induced on one field plot by withholding water, while a second plot remained irrigated and was used as a control. Recorded variables included stem traits (e.g. biomass) and leaf structural (e.g. leaf area) and functional traits [e.g. intrinsic water use efficiency (Wi) and carbon isotope discrimination (Delta)]. Productivity and Delta displayed large genotypic variability and were not correlated. Delta scaled negatively with Wi and positively with stomatal conductance under moderate drought, suggesting that the diversity for Delta was mainly driven by stomatal conductance. Most of the productive genotypes displayed a low level of drought tolerance (i.e. a large reduction of biomass), while the less productive genotypes presented a large range of drought tolerance. The ability to increase WUE in response to water deficit was necessary but not sufficient to explain the genotypic diversity of drought tolerance.
authors.affiliation: Laboratoire de Biologie des Ligneux et des Grandes Cultures, UPRES EA 1207, UFR-Faculté des Sciences, Université d'Orléans, rue de Chartres, BP 6759, 45067 Orléans Cedex 02, France.
authors.forename: Romain
authors.initials: R
authors.lastname: Monclus
authors.forename: Erwin
authors.initials: E
authors.lastname: Dreyer
authors.forename: Marc
authors.initials: M
authors.lastname: Villar
authors.forename: Francis M
authors.initials: FM
authors.lastname: Delmotte
authors.forename: Didier
authors.initials: D
authors.lastname: Delay
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Petit
authors.forename: Cécile
authors.initials: C
authors.lastname: Barbaroux
authors.forename: Didier
authors.initials: D
authors.lastname: Le Thiec
authors.forename: Claude
authors.initials: C
authors.lastname: Bréchet
authors.forename: Franck
authors.initials: F
authors.lastname: Brignolas
mesh_terms: D018533:Biomass; D002244:Carbon / Q000378:metabolism; D003433:Crosses, Genetic; D003681:Dehydration; D014644:Genetic Variation; D005838:Genotype; D009584:Nitrogen / Q000378:metabolism; D010788:Photosynthesis; D018515:Plant Leaves / Q000033:anatomy & histology / Q000254:growth & development / Q000378:metabolism; D032107:Populus / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D014867:Water / Q000378:metabolism*
chemical_list: D014867:Water; D002244:Carbon; D009584:Nitrogen