Carbon isotope discrimination, photosynthetic gas exchange, and transpiration efficiency in beans and range grasses

Abstract

Carbon isotope discrimination (Δ) provides an integrated measure of the ratio of intercellular to ambient CO2 concentrations in C3 photosynthetic pathway plants. Both of these parameters are related to gas exchange processes within leaves. Variations in the Δ values for common bean Phaseolus vulgaris and a range grass (Agropyron desertorum) are reviewed. Δ values exhibit phenotypic plasticity, but appear to be stable across developmental stages, habitats, and seasons. Δ values appear to be correlated with transpiration efficiency, leaf conductance to water vapor, and dry matter production across the range of genotypes examined for both species. -from Authors