title: Vulnerability to drought-induced cavitation in poplars: synthesis and future opportunities.
abstract: Vulnerability to drought-induced cavitation is a key trait of plant water relations. Here, we summarize the available literature on vulnerability to drought-induced cavitation in poplars (Populus spp.), a genus of agronomic, ecological and scientific importance. Vulnerability curves and vulnerability parameters (including the water potential inducing 50% loss in hydraulic conductivity, P50) were collected from 37 studies published between 1991 and 2014, covering a range of 10 species and 12 interspecific hybrid crosses. Results of our meta-analysis confirm that poplars are among the most vulnerable woody species to drought-induced cavitation (mean P50  = -1.44 and -1.55 MPa across pure species and hybrids, respectively). Yet, significant variation occurs among species (P50 range: 1.43 MPa) and among hybrid crosses (P50 range: 1.12 MPa), within species and hybrid crosses (max. P50 range reported: 0.8 MPa) as well as in response to environmental factors including nitrogen fertilization, irradiance, temperature and drought (max. P50 range reported: 0.75 MPa). Potential implications and gaps in knowledge are discussed in the context of poplar cultivation, species adaptation and climate modifications. We suggest that poplars represent a valuable model for studies on drought-induced cavitation, especially to elucidate the genetic and molecular basis of cavitation resistance in Angiosperms.
authors.affiliation: INRA, LBLGC, EA 1207, University of Orléans, Orléans, F-45067, France.
authors.forename: Régis
authors.initials: R
authors.lastname: Fichot
authors.affiliation: INRA, LBLGC, EA 1207, University of Orléans, Orléans, F-45067, France.
authors.forename: Franck
authors.initials: F
authors.lastname: Brignolas
authors.affiliation: UMR547 PIAF, INRA, Clermont-Ferrand, F-63100, France.|UMR547 PIAF, Clermont Université, Université Blaise-Pascal, Clermont-Ferrand, F-63000, France.
authors.forename: Hervé
authors.initials: H
authors.lastname: Cochard
authors.affiliation: Department of Biology, Centre of Excellence, Plant and Vegetation Ecology (PLECO), University of Antwerp, Wilrijk, B-2610, Belgium.
authors.forename: Reinhart
authors.initials: R
authors.lastname: Ceulemans
mesh_terms: D000064:Acclimatization; D055864:Droughts; D004777:Environment; D009584:Nitrogen / Q000378:metabolism; D018526:Plant Transpiration / Q000502:physiology*; D032107:Populus / Q000033:anatomy & histology / Q000502:physiology*; D013045:Species Specificity; D014867:Water / Q000502:physiology*; D014934:Wood / Q000033:anatomy & histology / Q000502:physiology; D052584:Xylem / Q000033:anatomy & histology / Q000502:physiology
chemical_list: D014867:Water; D009584:Nitrogen
keywords: Populus; genetic variation; interspecific hybrids; phenotypic plasticity; pure species; trade-offs; water deficit; xylem anatomy