【摘要】 利用热脉冲技术对胡杨树干液流进行了研究,分析了胡杨树干液流日变化、不同胸径树干液流流量及胡杨液流的变化规律和其主要影响因子的关系。结果表明:在正常生长状态下,胡杨树干单位面积液流通量为0.450L/(cm2.d),在4~8月生长期内,日平均耗水量为78.335 L/d。胡杨树干断面单位时间内液流量变化呈明显的昼夜节律,白天的流速变化曲线呈双峰型,夜间树干液流速度处于平稳的低值,白天10:00与午后18:00左右达到两个峰值。随着胸径的增大,树干液流速度和液流量也随之增大。最后从理论分析着手建立2种类型的胡杨蒸腾模型,并用监测资料进行了验证。更多还原

【Abstract】 It is very and necessary important to research water consumption of natural vegetation and its characteristics in arid zone in order to maintain and revive ecological system of oasis especially in Tarim river basin.The heat pulse method for measuring sap flow in plants stem was developed and tested to provide a means for investigating transpiration of single plants under conditions without disturbing the environment.In this paper,the heat-pulse technique was applied to study the stem sap flow of Populus euphrtaicr in water-balance station in Akesu.We investigated the diurnal variation of stem sap flow,the variation of sap flow with different diameters of cross section and the variant characteristics of stem sap flow of Populus euphrtaicr in different areas.The experimental results show that,in the natural conditions,the intensity of sap flow of Populus euphrtaicr was 0.450 L/(cm2·d).During the growth season from April to August,the water consumption of Populus euphrtaicr is 78.335 L/d.Daily changes of stem sap flow of Populus euphrtaicr in this study obviously have a temporal regularity.In daytime,the diurnal variation of sap flow of Populus euphrtaicr shows dual-peaks characteristics.While at night,the speed of sap flow is steadily lower.It has two peaks at 10:00 and 18:00 respectively.For different diameters of cross section of Populus euphrtaicr,the speed of stem sap flow is different.The diurnal change of volume of sap flow showed minor fluctuations closely related to the change of micrometeorological factors.Moreover,it established the mathematical model being verified by the data of actual measurement.Among the transpiration models of Populus euphrtuicr, semi-experiential model is the most ideal.更多还原