The Exploration Research To The Mechanism Of Submerged Plant Ecology Restores

In the past few years, the intensive human activities have greatly effects on the degradation of lakes, the deterioration of water quality and the lack of multi-required functions. The coupling of source controling and ecological restoration is a new idea in the current research on the control of lake pollution. The research of restoration and maintenance of aquatic vegetation in polluted lake is the key issue all over the world. The restoration of lake aquatic vegetation is also regarded as a key segment for ecology restoration. The researches on restored mechanism and the application of engineer techniques were developed in China. Consequently, as the research programe of" the ninth five-year plan ", "the tenth five-year plan" and 2010 Program were directed to deal with the pollution of Taihu Lake. Moreover, the "973" programe and 15th Key Scientific and Technical Special Project were boosting for the Taihu Lake project.This study was based on the sub-project" Mechanism of Degenerates and Restores of the Aquatic Vegetation (2002CB412307)" of the " 973 " Project -" Research of Lake Eutrophication Process and Blue-Green Alga Eruption Mechanism". This paper summarized the restored games for degenerated lake ecosystem in China and illustrated the status, functions, impact factors, and necessity of lake aquatic vegetation. According to the investigation on the local situation of aquatic vegetation in Littoral Regions of Gonghu Lake and Meiliang Bay of the Wuxi Taihu Lake, the species of aquatic vegetation, community forms and biomass were acquired. Then a contrast of vegetation distribution characteristic between the two Littoral Regions was analyzed which induced to the analysis of impact factors. In the treatments designed as varying degree oxidation intimidate, the heavy metal cadmium and the ammonia nitrogen single and compound poisons, the COD sewage cultivate, the plant growth opsonin(chitosan) processes, the effect of the intimidate environment on the submerged plant growth and the physiological biochemistry characteristic was analyzed. The effective method to improve the resist adversity of submerged macrophyte was discussed. The results will give a suggestion to the restoration of the submerged macrophyte, the efficiency and reconstruction in Lake Ecosystem. The dissertation research conclusion is as follows :1. Meiliang bay to be contrasted with Gonghu lake, the water quality pollution isseriously, the sort of water plant is little, the cover degree is low, biomass is little, the marked divergence in transparency >TNNTP>and CODMn's concentration of the two lakes is the significant effect element that causes distribution divergence of submerged macrophyte.2. The suitable oxidative stress can reduce the content of MDA, strengthen activity of Antioxidatase(SOD> CAT), thus improve cold tolerance of Hydrilla verticillata.3. Under the stress of ammonia nitrogen and cadmium, Myriophyllum Spicatum expresss out the powerfuler tolerance capability than Hydrilla verticillata, Especially the ammonia nitrogen, compound poisons of cadmium and ammonia nitrogen, come into jointly harming to Hydrilla verticillata.4. Under the stress of cadmium, chlorophyll synthesizes of Hydrilla verticillata obviously drop, Antioxidatase(SC^ POD) have a tendency that briefly to ascend , then drops one by one.5. Chitosan can cut down the germinateing cycle of Seed, Lift the germination rate of seed, accelerate the growth of submerged macrophyte, strengthen activity of Antioxidatase, heighten the tolerance capability to the intimidate environment, the fit concentration of chitosan is affiliated with sort of submerged macrophyte.6. Chitosan can improve the photosynthesis system of plant, heighten the tolerance capability to the intimidate environment, alleviate the extent of damage that the intimidate environment probably produce. The significant element of determining the fit concentration of chitosan is the sort and the surface area of submerged macrophyte.