Water Stress, Water Use Efficiency, Carbon Isotope Discrimination and Leaf Gas Exchange Relationships of the Bush Bean

Abstract

Abstract Water use efficiencies for the whole plant (WUE 1 ) and single leaves (WUE 1 ) were studied in a greenhouse as a function of soil moisture during four phenological stages of bush bean growth. WUE 1 increased significantly with soil moisture stress and attained its maximum value before the flowering stage. WUE 1 and WUE 1 were linearly related ( r = 0.92), and WUE 1 was correlated with the transpiration rate ( r = ‐0.87), stomatal conductance ( r = ‐0.80) and photosynthetic rate ( r = 0.81). Carbon isotope discrimination.), decreased as soil moisture decreased, and) was negatively correlated with both WUE 1 ( r = ‐0.92) and WUE 1 ( r = ‐0.88). There were significant differences in leaf N among water regimes.