The Characteristic Of Soil Seed Banks In Taihu Lake And Its Function In Ecological Restoration For The Polluted Water Environment

Lake eutrophication is a serious problem in china, the most corresponding eco-reconstruction countermeasures were set up based on the analysis of conditions of hydrology, water quality and sediment. The investigation and countermeasures included pollution sources control, habitat rehabilitation to create the conditions for ecological restoration, optimum design for artificial restoration of aquatic vegetation and aquatic ecosystem management, and the technology of soil seed banks is an efficient measure for restoration of aquatic vegetation of eutrophicated lake. Based on the feasibility and application advantage of soil seed banks in restoration of aquatic vegetation of lake eutrophication, the paper studied the characteristic of soil seed banks of East Taihu lake, the restoration effect on aquatic vegetation and rehabilitation of water environment. The main results were summarized as follows:The identification of soil seed banks was carried out through incubation experiment in laboratory condition, we found out the size of soil seed banks for three dominant aquatic plant community in lake Taihu is examined and the order in magnitude is: vallisneria spiralis L community > potamogeton malaianus community > potamogeton maackianus community. And because of different reproduction characteristic of various submerged plant, composition structure of the tested soil seed banks showed difference: the germination of vallisneria spiralis L is mostly by tuber (tuber account for 69% and seed account for 31%, respectively) ; the germination of potamogeton maackianus is mostly by seed (seed account for 98% and break tress account for 2%, respectively); potamogeton malaianus is germinated by both tuber and seed. The germination of vallisneria spiralis L is early and rapid; The germination of potamogeton malaianus is late but rapid in the laten stage; The germination of potamogeton maackianus is moderate. The species quantity of submerged plant investigated from three experiment plots of East Taihu lake,shed and Wuli lake are bigger than obtained by laboratory incubation.The late dominant aquatic plant community germinated by soil seed banks and artificial transplanting plots is Hydrilla verticillata community, and it showed that Hydrilla verticillata has good adaption for this experimental conditions. The aquatic plant community established by soil seed banks have better species variety than artificial transplanting plots.Soil seed banks could restorate the water environment quality effectively, and reduce the content of total phosphorus,chlorophyll and chemical oxygen demand of the polluted water environment evidently.