内陆干旱区典型旱生植物蒸腾耗水量模拟研究

内陆干旱区植物耗水量是生态恢复和水资源管理的重要依据。参照甘肃省民勤县青土湖附近气象条件、干旱区典型植物生理特征以及土壤水力特征参数，采用Tardieu-Davies模型（气孔导度模型），计算在适宜和极限生态地下水埋深下7种典型植物生长季蒸腾耗水量，并与国内外研究成果对比，得出以下结论：适宜、极限生态地下水埋深下，7种植物生长季内平均蒸腾量分别为793、602 mm。不同植物蒸腾量差异大，适宜生态地下水位埋深下水生植物芦苇（Phragmites australis）、河岸带植被柽柳（Tamarix chinensis）蒸腾量最大，分别为1292、1147 mm；耐旱性强的荒漠植被梭梭（Haloxylon ammodendron）蒸腾量最小，为279 mm；其它植被盐节木（Halocnemum strobilaceum）（940 mm）、罗布麻（Poacynum hendersonii）（913 mm）、白刺（Nitraria tangutorum）（534 mm）、胡杨（Populus euphratica）（448 mm）蒸腾量依次减小。由适宜生态地下水埋深降低至极限生态地下水埋深时，植物蒸腾量平均减少24%。耐旱性强的梭梭、白刺减幅大，分别为53、35%；耐旱性弱的芦苇、柽柳减幅小，分别为19、13%。

Simulation of transpiration for typical xeromorphic plants in inland arid region of Northwestern China

Plant transpiration is of great importance in restoration and water resources management, especially, in inland arid region of Northwestern China. In this study, based on the meteorological data of Qingtu Lake in Minqin County, Gansu Province of China, the physiological parameters of the seven typical desert plants, and soil hydraulic characteristics in the inland arid region of China, the transpirations of the seven typical plants were simulated by the Tardieu-Davies model. Moreover, since the xeromorphic plants rely on depth to groundwater. The plant transpiration modelling is executed in the two soil moisture conditions in root zone maintained by groundwater. The soil moistures were roughly estimated by the Van Genuchten model at the depths to groundwater table that were suitable and could lead to extinction for plant growth. The modeling obtained hourly and daily transpiration in the ten years during 2009-2018. Compared to the collected data from the published literatures, our simulated transpirations of the seven typical plants during growing season (April-September) were proven to be reasonable. The modeling results show that the mean transpiration of the seven plants during growing season under the suitable and the extinction depths is 793 and 602 mm, respectively.The transpirations of individual plant species during growing season were different. Under the condition of the suitable depth, the transpirations of Phragmites australis of aquatic plant and Tamarix chinensis of riparian plant were largest, which were 1292 and 1147 mm in growing season, respectively; by contrast, Haloxylon ammodendron needs the least water for transpiration (279 mm) as Haloxylon ammodendron can resists extremely dry climate. The transpirations of the other plant species decrease in the order as follows:940 mm for Halocnemum strobilaceum, 913 mm for Poacynum hendersonii, 534 mm for Nitraria tangutorum, and 448 mm for Populus euphratica in growing season. When the suitable depth declines to the extinction depth, the plant transpiration during growing season decreases by 24%, on average. The decreases of plant transpirations were also different for different plant species. Since Haloxylon ammodendron and Nitraria tangutorum have strong capacity of drought tolerance, their transpirations decrease markedly with depth to water table, e.g., 53 and 35%, respectively, when the suitable depth declines to the extinction depth. Phragmites australis and Tamarix chinensis have low capacity to resist drought. Thus, their transpirations decrease least with the depth to water table, e.g., 19 and 13%, respectively. For the other plant species, when the suitable depth declines to the extinction depth, the transpirations of Populus euphratica, Poacynum hendersonii, and Halocnemum strobilaceum decrease by 33, 25 and 25%, respectively.