Effects of polluted sediment in Dongwuli Lake on the germination of Potamogeton crispus turions and the growth of Hydrilla verticallata.

To explore the feasibility of restoration of submerged macrophytes in Dongwuli Lake,on the basis of the study of pollution index of the sediment,two typical submerged macrophytes which grew easily and were seasonally complementary in Meiliang bay and Gong lake were selected,and an experiment on the germination of Potamogeton crispus turions and the growth of Hydrilla verticallata were conducted.The result was as following: In sediment of Dongwuli Lake,the sequence of heavy metal pollution ranked as Cd,Cu,Pb,Zn and Cr.Although the the germinability of Potamogeton crispus turions in different sediment has no significant statistic difference(P0.05),turion dormancy was found under the stress of the sediment in Dongwuli Lake.In the same sediment,at different level of nitrogen(N) and phosphorus(P) of overlying water,the enzyme activity display was no statistic disparity(P0.05).In the different sediment,at same level of nitrogen(N) and Phosphorus(P) of overlying water,statistic analysis of enzyme activity of parried samples was apparent distinction(P0.05).Sediment of Dongwuli Lake quickened the aging process of Hydrilla verticallata.Sediment was the key factor to affect antioxidant enzyme of the submerged plants,and the stress of Cd of the sediment was the main reason.