采用热平衡包裹式树干茎流测量系统(Stem Heat Balance,SHB)和自动气象站观测沙木蓼生长季茎干液流以及环境因子,以揭示毛乌素沙地沙木蓼(Atraphaxis bracteata A.Los)蒸腾耗水规律。结果表明:1)沙木蓼液流具有明显的昼夜节律,启动、停止与日出、日落同步,夜间仍保持一定液流,以补充植物体水分亏缺。2)沙木蓼液流规律受天气影响显著:降雨时白天的液流速率大幅下降,夜间液流却大幅提升,日液流总量降至晴天的一半;阴天液流速率平缓,昼夜差距减小,液流总量较晴天小幅下降;多云天液流速率波动剧烈,但总液流量变化不大。3)沙木蓼生长季的液流量与土壤水分状况和植物体的生长阶段密切相关,6、7月份沙木蓼植株处在旺盛的营养生长阶段,新叶生长迅速,加上土壤含水充足,液流量总体是增长趋势,从7月末到8月份沙木蓼植株从营养生长期过渡到生殖生长以开花结果为主的阶段,蒸腾减小,同时天气干旱土壤水分逐渐亏缺,液流量呈下降趋势。4)从6月到8月基茎9mm,16mm,25mm的沙木蓼总耗水分别为100.8kg,170.5kg,301.3kg。沙木蓼植株生长季茎干液流总量基本与基茎成正比,平均为11.5kg/mm/a,可以用来作各个茎级沙木蓼植株的茎干液流推算,进而推算已知林分的总蒸腾耗水量。 The Stem Heat Balance (SHB) and automatic weather station were used to observe the stem flow and the environmental factors during the growing season of Polygonum viviparum to reveal the transpiration of Atraphaxis bracteata A.Los in the Mu Us Sandy Land Water consumption law. The results showed that: 1) Polygonum viviparum had a significant circadian rhythm, which started and stopped synchronously with sunrise and sunset, maintained a certain flow at night to replenish water deficit in plants. 2) The law of flow of Polygonum viviparum was significantly affected by the weather: during the daytime, the flow rate during the day dropped sharply, the flow rate at night increased sharply, and the total daily flow dropped to half of the sunny day. The overcast flow rate was flat and the day-night gap The total amount of liquid flow decreased slightly compared with that of sunny day; the flow rate of cloudy day fluctuated violently, but the total liquid flow did not change much. 3) The flow rate of Polygonum viviparum during the growing season is closely related to the soil moisture status and plant growth stage. In June and July, Polygonum amygdaloidum is in vegetative growth stage with rapid growth of new leaves. With abundant soil water, The liquid flow rate was generally increasing. From the end of July to August, the plantlet transpiration from vegetative stage to reproductive stage mainly took flowering stage, and the transpiration decreased. At the same time, the soil moisture in the arid climate was gradually reduced and the liquid flow rate decreased trend. 4) The total water consumption of Polygonum grandis from 9 months to 16 months from June to August was 100.8kg, 170.5kg and 301.3kg respectively. The total amount of stem sap flow in Polygonum polygamum plant during the growing season was basically proportional to the basal stem, with an average of 11.5 kg / mm / a, which could be used to calculate the stem flow of the plants of Polygonum amygdaloidum The total transpiration water consumption.