The Screening Of The Stable Plant In Permafrost Degraded Area And The Research Of Its Adaptation Mechanisms In Qinghai-Tibet Plateau

The Permafrost ecosystems of Qinghai-Tibet Plateau (QTP) are very sensitive to outside interference and fragile ecosystems. Because the situation of the global climate has gradually deteriorated and the strength of human activities in this region is growing, the permafrost in QTP shows a trend of serous degradation. Therefore, the plant comm unities in the degraded areas are greatly influenced:the species diversity is decreasing; the productivity changes and the vegetation types show adverse succession. Nowadays, Because of the harsh natural environment and the more strong impact of interference in this region the ecological restoration is always facing many difficulties. However, we must carry out a profound study of the changes in the ecosystem in QTP due to its significance, and get constructive theory of ecological restoration.Based on those reasons, in this paper, the object of the study in this research is the vegetation characteristics along the Qinghai-Tibet Highway (from Xidatan to Nagqu section, QTH). Main results are as follows:1. Species encountered in the quadrat survey along the road, after specimen collection, identification, edited Plant List for the Qinghai-Tibet Highway (from Xidatan to Nagqu section QTH).2. We survey the basic characteristics of the plant community in the sample plots along the highway, and analyze the dominant species of vegetation, mainly associated species and the species diversity in some sample plots. The results showed that:The composition of family and genus of the plant ecosystem in this region have close contact In permafrost degradation process, the species composition in the genus range and the species richness decreased. Reduced species diversity and primary productivity of the ecosystem affect the ecosystem stability. Species diversity and primary productivity has a close parabolic relationship.3. According to the established screening criteria in this paper, combined with field survey, we screen plant species with the natural stability in the geographic ranges during the permafrost degradation process. Finally, we established Kobresia pygmaea is an ideal target species. 4. A preliminary study of the physiological adaptation mechanism for this stability plant species was conducted. We detected the physiological changes in a sample under artificial interference conditions and elevation changes. The experimental results showed that:The artificial interference cause a significant decline in most samples within proline, non-structural carbohydrate content and carbon stable isotope composition. The situation of MDA content is contrary. The influence of this interference in the sucrose metabolism related enzymes change is not obvious. This interference effect significantly reduces the correlation between the samples of physiological indicators and elevation gradient.