Photosynthesis and Water Use Efficiency of Platycladus Orientalis and Robinia Pseudoacacia Saplings under Steady Soil Water Stress during Different Stages of Their Annual Growth Period  

作　　者：Ming-Chun Wang Jin-Xin Wang Qing-Hua Shi Jin-Song Zhang 

机构地区：[1]College of Forestry Northwest A&F University Yangling, Shaanxi China712100 [2]College of Resources and Environment Northwest A&F University Yangling, Shaanxi China712100 [3]Research Institute of Forestry Chinese Academy of Forestry, Beijing China100091

出　　处：《Journal of Integrative Plant Biology》2007年第10期1470-1477,共8页植物学报（英文版）

基　　金：Supported by the National Natural Science Foundation of China(30371151);the State Key Basic Research and Development Plan of China(2002CB111506);the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry.

摘　　要：A simulated drought experiment was conducted in a rain-free shed to test the physiological response of Platycladus orientalis and Robinia pseudoacacia saplings to steady soil water stress during different stages. The five soil water treatments were： 100%, 87.84%, 70%, 52.16% and 40% of field capacity. The results showed that the net photosynthetic rate of R. pseudoacacia decreased as soil water potential decreased in the range between -0.041 MPa and -0.292 MPa. The threshold value at which the net photosynthetic rate changed significantly was -0.12 MPa. The relationship between net photosynthetic rate of P. orientalis and soil water potential could be described as a quadratic parabola in the range between -0.041 MPa and -0.648 MPa. Analysis of variance showed significant differences in the net photosynthetic rate of P. orientalis between soil water potentials of -0.061 MPa ~, -0.648 MPa. Average water use efficiency （WUE） increased as soil water potential decreased, but the influence mechanism of soil water stress on leaf WUE and photosynthetic rate for the two species were different evidently.A simulated drought experiment was conducted in a rain-free shed to test the physiological response of Platycladus orientalis and Robinia pseudoacacia saplings to steady soil water stress during different stages. The five soil water treatments were： 100%, 87.84%, 70%, 52.16% and 40% of field capacity. The results showed that the net photosynthetic rate of R. pseudoacacia decreased as soil water potential decreased in the range between -0.041 MPa and -0.292 MPa. The threshold value at which the net photosynthetic rate changed significantly was -0.12 MPa. The relationship between net photosynthetic rate of P. orientalis and soil water potential could be described as a quadratic parabola in the range between -0.041 MPa and -0.648 MPa. Analysis of variance showed significant differences in the net photosynthetic rate of P. orientalis between soil water potentials of -0.061 MPa ~, -0.648 MPa. Average water use efficiency （WUE） increased as soil water potential decreased, but the influence mechanism of soil water stress on leaf WUE and photosynthetic rate for the two species were different evidently.

关 键 词：growth stages PHOTOSYNTHESIS Platycladus onentalis Robinia pseudoacacia SAPLING steady water stress water use efficiency. 

分 类 号：Q945.1[生物学—植物学]