短命植物在我国主要分布于新疆北部的准噶尔盆地及其毗邻的草原地带，是多种荒漠植物群落草本片层中的优势种或伴生种，在早春植物群落中具有很重要的地位。短命植物的存在成为新疆北部植被区别于我国其他荒漠植被和草原植被的重要特征。对短命植物气体交换特征进行研究可以为准噶尔荒漠物种多样性保育提供理论依据，对改善准噶尔荒漠植生态环境有重要的意义。选取莫索湾地区150团荒漠区的四种典型短命植物狭果鹤虱（Lappula. semiglabra）、四齿芥（Tetracme quadricormis）、卷果涩芥(Malcolmia scorpioides)和东方旱麦草(Eremopyrum orientale)作为研究对象。它们是准噶尔盆地荒漠区早春植物群落草本片层的优势种，无论多度还是盖度都占主导位置，具有较好的代表性。1．四种短命植物具有较强的光合能力，物种间光合能力差异不大。但光合能力随生长节律变化较大，生长盛期的光合能力是后期的2～3倍。光合能力与实际净光合速率之间的差值反映植物的光合潜力，其中卷果涩芥的光合潜力最大。2．物种间叶片净光合速率、蒸腾速率和水分利用效率的时间动态随物种、物候变化，各不相同，主要体现在变化类型、波动程度、峰值出现时间等。通过相关和逐步回归分析得出，影响净光合速率的关键因子是光合有效辐射，而胞间CO2浓度和蒸腾速率也是两个主要影响因子；蒸腾速率则主要受光合有效辐射、气孔导度和大气温度影响；水分利用效率受净光合速率的影响比蒸腾速率更大。3．根据实测数据拟合出四种短命植物对光照强度和CO2浓度的响应，其表观量子效率的排序为卷果涩芥>狭果鹤虱>东方旱麦草>四齿芥，其值分别为0.0691、0.0179、0.073和0.057。而狭果鹤虱和东方旱麦草的羧化效率则分别是0.0541和0.0362。

The distribution area of ephemeral plants in China is mainly in Dzungaria basin and its adjacent grassland, north part of Xinjiang Uygur Autonomous Region. The ephemeral plant communities play an important and special role in early spring vegetation in Dzungaria basin, which make the desert and grassland of Xinjiang difference from other area. The gas exchange characteristics of typical ephemeral plants could help us understanding the water utilization efficiency and other adaptation strategies, which could give us the accordance on the conservation and protection of diversity of desert plants in Dzungaria basin. Lappula semiglabra, Tetracme quadricormis, Malcolmia scorpioides and Eremopyrum orientale are dominant species of herb stratum in early spring vegetation in Dzungaria basin. Several main conclusions are shown as below.1. The four ephemeral plants show great photosynthetic capacity and low difference between species but high change in different seasons. The photosynthetic capacity in blooming period is 2-3 times higher than that in fruit period. Among the four species, M. scorpioides shows greatest photosynthetic potentiality.2. The diurnal course of net photosynthesis, transpiration and water use efficiency differ in change type, fluctuation, time of peak value and so on. According to correlation and stepwise regression analysis, photosynthetic active radiation is crucial for net photosynthetic rate whereas internal CO2 concentration and transpiration rate are two main impact factors. For transpiration rate, photosynthetic active radiation, stomatal conductance and air temperature are main impact factors. Net photosynthetic rate has greater influence on water use inficiency than that of transpiration rate.3. The fitting curves of net photosynthetic response to radiation and CO2 with field data shows apparent quantum yield of four ephemeral plants are M. scorpioides> L. semiglabra> E. orientale> T. quadricormis, which are 0.0691, 0.0179, 0.073 and 0.057 apparently. Carboxylation efficiency of L. semiglabra and E. orientale are 0.0541 and 0.0362.