title: Leaf hydraulic conductivity and photosynthesis are genetically correlated in an annual grass.
abstract: Comparative studies suggest that a positive correlation between xylem water transport and photosynthesis is adaptive. A requirement for the adaptive evolution of coordination between xylem and photosynthetic functions is the presence of genetic variation and covariation for these traits within populations. Here it was determined whether there was genetic variation and covariation for leaf blade hydraulic conductivity (K(W)), photosynthetic rate (A), stomatal conductance (g(s)), and time to flowering in a population of recombinant inbred lines of Avena barbata, a Mediterranean annual grass. Significant (P < 0.05) broad-sense heritabilities (H(2)) were detected for K(W) (H(2) = 0.33), A (H(2) = 0.23) and flowering time (H(2) = 0.62), but not for g(s). Significant positive genetic covariation between A and K(W) was also observed. There was no other genetic covariation among traits. The first evidence of genetic variation for K(W) within a species was obtained. These results also indicate that there is a genetic basis for the positive association between xylem water transport and photosynthesis. The presence of significant genetic variation and covariation for these traits in natural populations would facilitate correlated evolution between xylem and leaf functions.
authors.affiliation: Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G2W1, Canada.
authors.forename: Hafiz
authors.initials: H
authors.lastname: Maherali
authors.affiliation: Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G2W1, Canada.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Sherrard
authors.affiliation: Department of Integrative Biology, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G2W1, Canada.
authors.forename: Megan H
authors.initials: MH
authors.lastname: Clifford
authors.affiliation: Department of Biology, Dalhousie University, 1355 Oxford St, Halifax, Nova Scotia B3H 4J1, Canada.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Latta
mesh_terms: D001692:Biological Transport; D018533:Biomass; D001696:Biomechanical Phenomena; D014644:Genetic Variation; D010641:Phenotype; D010788:Photosynthesis / Q000235:genetics*; D018515:Plant Leaves / Q000033:anatomy & histology / Q000235:genetics / Q000378:metabolism; D054046:Plant Stomata / Q000502:physiology; D006109:Poaceae / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D014867:Water / Q000378:metabolism*; D052584:Xylem / Q000235:genetics / Q000378:metabolism
chemical_list: D014867:Water