内蒙古库布其沙地小叶锦鸡儿水势研究

Study on the Water Potential of Caragana microphylla in Kubuqi Desert Land of Inner Mongolia

[目的]初步研究小叶锦鸡儿水势日变化、月变化及其与环境因子之间的关系。[方法]采用PSYPRO水势仪测定库布齐沙地小叶锦鸡儿的叶水势,对叶水势日变化、月变化进行动态研究,并分析其和水分在SPAC系统中的运移过程。[结果]小叶锦鸡儿叶水势的日进程在5、9月份呈单峰曲线变化,6～8月份则表现为双峰曲线变化。15:00左右通常是一天中叶水势的最低值。叶水势与大气温度和光照呈显著负相关,而与大气相对湿度呈正相关,相关系数为0.88。大气相对湿度对植物水势的影响最大。水分在SPAC系统中运移的主要阻力发生在叶-气界面。水分在小叶锦鸡儿体内运移过程中,植物体内部茎-叶的水势差(0.077MPa)远远小于根-茎的水势差(1.050MPa)。[结论]该研究为库布齐沙地的植被恢复与重建提供了理论依据和参考。

[Objective] The propose was to preliminarily research on the daily changes and month change for the water potential of Caragana microphylla and their relationship with the environmental factors.[Method] The leaf water potential of C.microphylla was measured by PSYPRO water potential meter in Kubuqi desert land.The dynamic study on the daily and month changes of leaf water potential was made,and the water potential and water in the migration process of soil plant atmosphere continuum（SPAC）system were analyzed.[Result] The day process of leaf water potential in C.microphylla showed the change of single-peak type in May and September and showed the change of double-peak curves from June to Augest.The minimum peak value of water potential took place around 15 ：00 in a day.The leaf water potential had a negative correlation to the atmospheric temperature and the illumination and a positive correlation to the atmospheric humidity,with the correlation coefficient of 0.88.The atmospheric relative humidity had the greatest impact on the plant water potential.The main resistance for water movement in the SPAC system occurred in the leaf-air interface.During the water was moved within the plant of C.microphylla,the stem-leaf water potential difference（0.077 MPa）in the plant was far less than the root-the stem water potential difference（1.050 MPa）.[Conclusion] The study provided the theoretical basis and reference for the vegetation restoration and reconstruction of Kubuqi desert land.