CHANGES OF CHARACTERISTICS OF THE LEAF EPIDERMIS AND GENETIC DIVERSITY OF CARAGANA DAVAZAMCII IN DIFFERENT HABITATS IN ERDOS PLATEAU, CHINA Studies on the photosynthetic physiology of Spirulina erdosensis Biodiversity of shrub community in desert steppe and steppe desert on Erdos plateau Genetic structure of Caragana davazamcii Sancz along a precipitation gradient in Erdos Plateau Spatial pattern of Nitraria Tangutorum shrub islands based on transect