Variability in mesophyll conductance between barley genotypes, and effects on transpiration efficiency and carbon isotope discrimination

Abstract

Leaf internal, or mesophyll, conductance to CO2 (gm) is a significant and variable limitation of photosynthesis that also affects leaf transpiration efficiency (TE). Genotypic variation in gm and the effect of gm on TE were assessed in six barley genotypes (four Hordeum vulgare and two H. bulbosum). Significant variation in gm was found between genotypes, and was correlated with photosynthetic rate. The genotype with the highest gm also had the highest TE and the lowest carbon isotope discrimination as recorded in leaf tissue (Δp). These results suggest gm has unexplored potential to provide TE improvement within crop breeding programmes. Show more