沙漠人工植被区柠条树干液流变化及影响因子分析

Stem Sap Flow of Caragana korshinskii and Its Influence Factors in a Revegetated Desert Area

于2008年5—9月利用Dynamax茎流仪测量了沙坡头地区18 a龄人工柠条的树干液流速率,并利用涡动相关系统同步监测了环境因子,分析柠条液流的变化规律及其与环境因子的关系。结果表明,观测期间柠条液流速率均表现为明显的单峰曲线,液流一般在00:00左右启动,08:30—11:30达到高峰,然后下降,在午夜时分达到最低。对液流速率与环境因子的相关分析表明,太阳辐射、相对湿度、空气温度、风速等因子显著影响到柠条的液流速率,其中太阳辐射和相对湿度的影响最为显著,经过逐步回归建立了该区柠条液流速率与环境因子的多元线性方程。

Stem sap flows of 18-year-old Caragana korshinskii plants were monitored continuously with Dynamax stem flow recorder for the entire growing season under nature conditions in a revegetated desert area.Environmental factors such as solar radiation,air temperatures,relative humidity,wind speed,and precipitation were measured meanwhile with eddy correlation system.Results show that the curves of stem sap flow rate in the whole growing season are obviously single-peak.Sap flow usually starts at 00：00 and increases gradually,reaches peak point at about 08：30—11：30,then gradually decreases to the minimum point at the middle night.Sap flow rate is significantly correlated with solar radiation,vapour pressure deficit,relative humidity,air temperature and wind speed,among which the solar radiation and relative humidity are two main factors that affect the sap flow rate of Caragana korshinskii.The close correlation between daily sap flow rate and meteorological factors in the whole growing season provides us an accurate estimation of the transpiration of Caragana korshinskii and rational water carrying capacity of sand dunes in the revegetated desert areas.Lastly,multiple linear equation of sap flow rate and environmental factors is established through stepwise regression.