荒漠区柽柳液流特征及其与环境因子的关系研究

Flow Characteristics of Tamarix in Desert Region and Its Relationship with Environmental Factors

干旱荒漠区植被水分传输状况决定着区域生态需水量,进而影响生态安全。植物的茎干液流量表征其蒸腾耗水量,能够准确反映单株植物的蒸腾作用和水分利用状况。本文以古尔班通古特沙漠南缘典型荒漠植被柽柳为研究对象,采用茎热平衡法,对区域典型荒漠植被柽柳茎干液流及其与环境因子的关系进行了研究,结果表明:①柽柳茎干液流日变化曲线呈多峰格型,日平均液流率为0.003 99g/s,最大值为0.013 5g/s。茎干液流7:00～15:00一直保持较高值(0.003g/s以上),21:00左右液流速率降到极低值;②柽柳风速变化和茎干液流速率存在相关性,微风可加快茎干液流,强风对茎干液流有抑制作用,而冠层温度与茎干液流速率呈正相关,冠层空气湿度与茎干液流呈负相关。

Arid desert vegetation evaporation status decides the regional ecological water demand, thereby affects the ecological security. Plant sap flow characterization indicates its transpiration water consumption and can accurately reflect the monoclonal plant transpiration and water utilization status. In this paper, the typical desertification vegetation Tamarix in the southern marginal zone of the Gurbantunggut desert is taken as sample, the stem sap flow and its relation with environmental factors is studied by using stem heat balance method. The results indicate that; （1）The Tamarix sap flow curve shows multiplypeak of grid type the average daily flow rate is 0. 003 99 g/s; the maximum value is 0. 013 5 g/s the sap flow maintains a high value, above 0. 003, at 7：00-15..00 and reduces to the lowest values around 21..00 2there exists correlation between the change of wind speed and the sap flow rate; The breeze speeds up the sap flow, while the strong wind inhibit the sap flow; the canopy temperature is positively related to the sap flow rate, while the air humidity is negatively related to the sap flow.