| Abstract: | The responses of photosynthesis, transpiration, respiration, leaf conductance and cuticular transpiration to water vapour pressure deficit (VPD) have been simultaneously measured in single attached leaves of soybean in order to test the mechanism in the effects of air humidity on photosynthesis and transpiration. The results of present experiments have shown that the affecting mechanism of VPD or air humidity on the photosynthesis and transpiration is by means of controlling not only the stomatal behavior, but also the cultivars behavior, and the stomatal closure at high VPD or low air humidity is a function of the cuticular transpiration, rather than the stomatal transpiration. |
