title: Variability in mesophyll conductance between barley genotypes, and effects on transpiration efficiency and carbon isotope discrimination.
abstract: Leaf internal, or mesophyll, conductance to CO(2) (g(m)) is a significant and variable limitation of photosynthesis that also affects leaf transpiration efficiency (TE). Genotypic variation in g(m) and the effect of g(m) on TE were assessed in six barley genotypes (four Hordeum vulgare and two H. bulbosum). Significant variation in g(m) was found between genotypes, and was correlated with photosynthetic rate. The genotype with the highest g(m) also had the highest TE and the lowest carbon isotope discrimination as recorded in leaf tissue (Delta(p)). These results suggest g(m) has unexplored potential to provide TE improvement within crop breeding programmes.
authors.affiliation: Landcare Research, PO Box 40, Lincoln 7640, New Zealand. margaret.barbour@sydney.edu.au
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Barbour
authors.forename: Charles R
authors.initials: CR
authors.lastname: Warren
authors.forename: Graham D
authors.initials: GD
authors.lastname: Farquhar
authors.forename: Guy
authors.initials: G
authors.lastname: Forrester
authors.forename: Hamish
authors.initials: H
authors.lastname: Brown
mesh_terms: D002247:Carbon Isotopes / Q000032:analysis; D014644:Genetic Variation; D005838:Genotype; D001467:Hordeum / Q000235:genetics* / Q000378:metabolism; D010788:Photosynthesis; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism*; D018526:Plant Transpiration
chemical_list: D002247:Carbon Isotopes