柠条抗旱的生理生态与土壤水分关系的研究

STUDIED ON THE RELATIONSHIP BETWEEN PHYSIOLOGICAL ECOLOGY OF DROUGHT-RESISTANCE IN CARAGANA KORSHINSKII AND SOIL WATER

采用LI－1600气孔计和压力室测试了风沙土上生长的柠条的SPAC系统的水分关系和P－V水分特征曲线，结果表明：当沙土含水率（W）的水分特征曲线的回归方程为：ψs=-40．32196×0．427905W，沙土平均含水率大于45％，柠条固沙林生长正常，叶水势高。沙土含水率小于4．5％时，柠条生长速度显著下降，柠条清晨叶水势（ψm）与沙土含水率（W）的回归方程为：ψm=－0．35926·e6．31144／W，风沙土上生长的柠条的“经济水阈”大约在4．5％左右，“生命水阈”大约在3．5％左右。

The paper has investigeted the physio-ecologicl water relationship of the SPACsystem and water parameters of P-V curver of Caragana korshiskii growing in aeolian sandysoil. When the relationship between water content(W) and water potential(ψs) in the aeoliansandy soil is: ψs=- 40. 32196 ×0.42795w, W= 4. 5 %, is just the poit that convert the slowlyfall into the fast one. When W>4. 5 % , C. korshinskii grows very well. And when W is bellowto 4. 5%, the growth has been affected by W. The leave water potential and transperationrage begin to fall step by step.The relationship between W and water potential (ψm) of leave measured in early morningis: ψm = - 0. 35926 ×e6.3114/W, and W = 4. 5 % is turning point while ψm converts the slowly fallinto the fast one and the fact that ψm = - 1. 46 MPa is above =-1. 81 MPa. It shows thatC. korshinskii may maintain the turgor potential in all night time. And W= 4. 5 % is the 'criti-cal value'that C. korshinskii could grow very well in the soil. When W = 3. 5 %, ψm = - 2. 18MPa is blow , which C. korshinskii can't maintain turgor potential and begin to die individu-ally.