An Analysis Of Biodiversity Character And Adaptive Evolution In West Ordos

Inner Mongolia west Ordos region was situated in the rim of ancient Mediterranean sea, it was the representative transition region from temperate desert grassland to desert in China There existed the endemic plants formed on the special natural background and made it particular region in arid and semi-arid area of Inner Mongolia and China. Many ancient relic species centrally distributed in the area, most of them were the constructive or dominant species of desert community, their existence played an important role in maintaining fraigle ecosystem. In this thesis, we discussed these species adaptive evolution through the geographical environment succession, main species morphological characters, breeding system and genetic diversity in the region. Following were the results:It experienced a series of geographical environment succession, however the Quaternary continental glaciation had not directly hit west Ordos and species survived in the suitable habitat after they went through different dry climate. Shrubs became dominant life form of adapting to environmental change in the area The origin, succession and distribution of shrub reflected ecological and geographical environment change, at the same time, it also reflected this habitat suited to species existence.Morphological structure of species had both general xerophtic traits and peculiar adaptive traits. Such as main root went deep into soil, lateral root and mechanical tissue of stem was well developed. The leave of the most species became smaller and lush epiderm was hairs and developed thick cuticle. The stoma had sunk and the palisade tissue was well developed The morphological structure traits could make effective use of water, decrease strong transpiration, strengthen photosynthesis and resist against drought stress. There were mucilage and crystal cells everywhere in the stems and...