Abstract: Regression analysis was used to study the relationship between four diversity indices and 19 soil factors at three different soil layers in ecotone between desert and oasis in Fukang,Xinjiang. The results indicated that soil pH,total salt content,soil organic matter,Cl^-,K⁺+Na⁺,Mg²⁺,total nitrogen,and available phosphorus were correlative to species diversity significantly (P<0.05). The relationships between pHand diversity and between organic matter and diversity were best fitted in form of binomial model,and it meant that the highest species diversity occurred in middle of the gradient. The relationships between diversity and other 6 indices were in form of negative linear regression,showing that the contents of total salt,Cl^-,K⁺+Na⁺,Mg²⁺ were greater,and the species diversity indices were smaller. And the regression of total nitrogen and available phosphorus with evenness were similar to the former,that is,with the contents of soil total nitrogen and available phosphorus increasing,evenness indices decline correspondingly. The results of regression analysis between amount of plants and soil moisture and salt showed that plant abundance was influenced by soil water and salt significantly (P<0.01).

Key words: Desert, Ecotone, Plant community, Species diversity, Soil factors, high temperature, over expression, PSⅡ activity, photosynthetic rate, cucumber., CsRCA