关键词: 荒漠植物, 生态化学计量学, 生境, 叶片

Abstract: Ecological stoichiometry is the study of the balance of multiple chemical elements in ecological interactions，it plays an important role in determining plants and ecosystem nutrient supply and their balance. The content of leaf chemical element is restricted by environmental nutrient availability，especially the restricted nutrient. Leaf nitrogen （N） and phosphorus （P） concentrations are two of the key traits which make important effect on the function and dynamics of ecosystem. Leaf N，P and N∶P vary with different species and sites. Study on the plants leaf nutrient content （N，P） and its variance in extreme environment is important not only in revealing the plants nutrient requirement and soil nutrient supply capacity，but also in revealing the plants adaptability to environment. Three typical sorts of desert plants，named Haloxylon ammodendron，Tamarix ramosissma and Calligonum mongolicunl，were involved in the study to investigate the effects of different habitats （Taklimakan Desert Botanical Garden - Botanical Garden，Gurbantonggut desert no irrigation shelterbelt - no irrigation shelterbelt，as well as their original habitats - original habitat） on three kinds of plant leaves ecological stoichiometry. The Two-Way ANOVA was used to determine the difference of soil and leaf C，N，P content and its stoichiometric ratio with various habitats. The results are as follows：in arid region，the surface soil presented as alkaline soil，soil salinity was significantly higher（4 mS·cm^-1）in the botanical garden than in other habitats （P<0.05），which can be explained as the saline irrigation and strong evaporation in this region. There is a similar trend of C，N，P content of soil in different habitats for both the original habitat and botanical gardens；T. ramosissma were higher，while the others were relatively low （P<0.05）. However，the largest C∶N and C∶P were presented at T. ramosissma original habitats，botanical gardens，no irrigation shelterbelt，and H. ammodendron original habitats followed，and the smallest was C. mongolicunl original habitat. There was no significant difference for N∶P at different habitats （P>0.05），which indicates that the arid soil remains relatively stable N∶P.  There are some differences for leaves C content of three plants，C. mongolicunl was the highest，T. ramosissma followed，H. ammodendron was relatively small （P<0.05），indicating that the there were some differences for C accumulation of three plants. However，plant leaf N，P content is mainly affected by the species，and the effects of habitats on plant leaves N，P content were not significant，the mean leaf N∶P is 15.91±0.68，and there is no significant difference between the different species in different habitats，this result indicates that leaves of plants in arid regions have a relatively constant N∶P. It also further illustrates the desert plants have relatively higher stability，thereby making them have a strong adaptability to extreme environment such as drought，barren and saline. The results of the research will be both a good supplement and a meaningful attempt for ecological stoichiometry in extreme environment.

Key words: desert plants, ecological stoichiometry, habitat, leaf