Water Use Efficiency And Response To Light Of Several Shrubs Indifferent Water Moisture In Datong Town In Qinghai

Aiming to solve the contradiction between demand for the extension of forest vegetation and the limited water supply in arid and semi-arid area and based on the theory of soil-plant-atmosphere continuum, the dissertation chose the main afforestation tree species to forest project in Growing Seasons in 2007,utilized advanced apparatus, equipments and various approaches, systematically analyzed of relationship between soil water content and light intensity and growing and photosynthesis characteristics. These studies could provides the scientific bases for accurately estimating ecological water consumption and the choice of tree species and the properly arrangement of stand density.The dissertation involved following aspects:1:Study on diurnal course of Zygophyllum xanthoxylon, Lycium potaninii Pojark, Shepherdia argentea in different soil water content;2:Study on reposing to light of Zygophyllum xanthoxylon, Lycium potaninii Pojark, Shepherdia argentea in different soil moisture;3:Study on suitable water content of Zygophyllum xanthoxylon, Lycium potaninii Pojark, Shepherdia argentea.By studying the result show that:The relation of diurnal course of photosynthetic rate , transpiration rate and water use efficiency of leaf and soil water content is close, and response to SWC is obvious, withered moisture of three shrubs is separately 6.67%,6.08%,6.79%.Study on the relation among photosynthesis rate, stomatal conductance, transpiration rate, water use efficiency and soil water content. The result show the suitable water content of Zygophyllum xanthoxylon is about 18.0%～27.0%, Lycium potaninii Pojark is 16.0%～24.0%,and Shepherdia argentea is about 16.0%～25.0%.Photosynthetic rate (Pn), transpiration rate(Tr) and water use efficiency of leaf(WUE) have clear threshold value response to photosynthetic active radiation. the fitting sphotosynthetic active radiation cause higher sunshine use efficiency and water use efficiency of Zygophyllum xanthoxylon is 800~1500μmol·m-2·s-1, the fitting sphotosynthetic active radiation cause higher sunshine use efficiency and water use efficiency of Lycium potaninii Pojark is 1000~1800μmol·m-2·s-1, the fitting sphotosynthetic active radiation cause higher sunshine use efficiency and water use efficiency of Shepherdia argentea is 1000~1500μmol·m-2·s-1.