Ecophysiological responses to drought stress in Salix psammophila C. Wang et Ch. Y. Yang and Salix matsudana Koidz

Ecophysiological responses to drought stress were investigated in cuttings of two Salix species, Salix psammophila C. Wang et Ch. Y. Yang and S. matsudana Koidz., which is used for afforestation in the Mu-us sandy land of Inner Mongolia, China. In this study, photosynthetic rate, transpiration rate, stomatal conductance and leaf water potential were measured using 3-month-old cuttings of both species grown under drought (-0.005 MPa in soil water potential) and control (well-watered) conditions. Under the drought stress treatment, S. matsudana showed decreases in transpiration rate through stomatal closure and maintained high value of leaf water potential, suggesting a high ability of dehydration postponement. S. matsudana also exhibited control of transpiration rate as a result of decreases in stomatal conductance during the drought treatment period, but these responses were less than S. matsudana. It was suggested that S. matsudana consumed more water under drought condition. Photosynthesis and growth of both species decreased as a result of drought stress. However, these decreases were less in S. matsudana than in S. psammophila.