沙枣树干液流的动态研究

Research on Dynamics of Stem Sap Flow of Elaeagnus angustifolia

利用热平衡方法，研究了黑河下游额济纳绿洲中沙枣（Elaeagnus angustifolia L．）树干液流的特点及其与环境因子的关系，结果表明：①在整个生长季的晴天，沙枣树干液流的日变化呈现明显的单峰窄峰曲线；液流在10：00时迅速上升，在12：00时达到高峰，14：00时又迅速下降；日累计液流为2．43L·d^-1，白天液流量占全天的92．6％～93．9％，晚上占6．1％～7．4％；由于存在根压，沙枣在夜间有微弱上升液流。②1月份液流量最小为22．0L；7月份最大，为76．6L；非生长季节的液流量占全年液流的35．6％；生长季节占64．4％。③生长季液流速率与环境因子逐步回归分析表明，树干液流受环境因子的综合影响，在日变化中大小依次是净辐射、总辐射、空气温度、风速和相对湿度，相关系数为0．69，决定系数为0．49；在季节变化中影响大小依次是空气温度，总辐射、净辐射、相对湿度和风速，相关系数和决定系数都是0.91。

The relationship between the stem sap flow of Elaeagnus angustifolia and environmental factors has been researched in Ejin oasis at lower Heihe river by using thermal equilibrium probe. Results are as follows： （1） During the growing season, the stem sap flow rate exhibited single-narrow peaked curve. It increases sharply after 10：00 and arrived at the peak around 12：00 and decreased sharply after 14：00. Daily accumulative water consumption is 2, 43 L. d^-1 ; Water consumption in daytime is 92.6% ～ 93.9% of a day, while in night it is 6.1%～7.4% ; The feeble sap flow of E. angustifia was occasionally observed at the night due to root pressure. （2） Average water consumption in Jan. is 22.0 L and it is the minimum in a year. Average water consumption in July is 76.6 L and it is the maximum; Water consumption in nongrowth season is 35.6% of the total year and 64.4% in growth season. （3） The result of progressively regression showed that the sap flow of woods was synthetically affected by environmental factors. The diurnal change of sap flow rate was closely related to the change of environmental factors. According to analysis resuits, the environment factors were ranked as： solar radiation, total radiation, air temperature, wind speed and relative humidity. Correlation coefficient is 0. 69 and deciding coefficient is 0.49. Environmental factors which affected seasonal change of sap flow were ranked as： air temperature, total radiation, solar radiation, relative humidity and wind speed. Correlation and deciding coefficient are 0.91.