关键词: 古尔班通古特沙漠, 梭梭, 茎干液流, 蒸腾耗水, 气象因子, 茎流热平衡技术

Abstract: Water consumption and transpiration of non-irrigated [Haloxylon ammodendron] in the hinterland of the Taklimakan Desert was studied based on the stem sap flow measured by Sakuratani stem flow gauge，and the corresponding meteorological data measured by a weather link. The results show that，the stem sap flow exhibits a bi-peaked or multi-peaked curve，with lower values at night than during the day. The ambiguous noon-depression phenomenon usually occurs during 14∶00～16∶00 from mid-May to the early September. Under the same environmental conditions，the larger the stem diameter，the larger the stem sap flow，and the more obvious the ambiguous noon-depression phenomenon. The daily changes of the sap flow are highest in June and lowest in September. There are differences in the monthly mean value in different plants，which may result from the differences in the crown and the number of assimilation organ. In the growing season，there are differences between the start and stop time of the stem sap flow. From June to August，the larger the stem diameter，the earlier the start time and the later the stop time is. There are also differences between the start and stop time of the same plant. The stem sap flow starts earlier and stops later in the beginning of the growing season and adversely at the end. The daily accumulation shows an “S” trend between May and the end of August，and shows a straight line with the same slope in September and October. The larger the stem diameter，the larger the daily water use and the accumulative rate are. The sap flow is influenced by meteorological factors，it is positively correlated with solar radiation，air temperature and wind speed，and negatively correlated with the air relative humidity，in which the solar radiation has the greatest impact on the sap flow [（Rmax=0.906）]. Under the same environmental condition，the larger the stem diameter，the better the correlation is. The correlation is the largest water use in July，and least in May and October. The larger the stem diameter，the more the water consumption is. The average daily water use of three individuals of [Haloxylon ammodendron] with a diameter of 9.9，13.4 and 22.9 cm is 0.570、0.295、0.694 mm，respectively，amounting to an annual water consumption of 92.904、96.923 and 113.052mm. The water use in the study area is less than that in other ecology environment，which implies the widely plasticity in the ecological water requirement. It would be the first choice to use [Haloxylon ammodendron] as the ecological restoration and reconstruction shrubs in the arid land. Moreover，there are obvious differences in the water use，the daily course，the correlation between the stem sap flow and the meteorological factors，which provides decision support in the management and the allocation of water resources for desert vegetation.

Key words: the Gurbantunggut Desert, aloxylon ammodendron, he stem sap flow, ranspiration, eteorological factors, he stem heat balance method