Effects Of Spirogyra And Microcystis On The Potential Of The Recovery During The Three Submerged Plants

Water eutrophication is the most urgent problem to China. And many findings suggested that the reconstruction and restoration of submerged macrophytes is a reliable approach to govern-eutrophication. In the implementation of water environment special item (the twelfth five-year plan) with respect to the governace of Dianchi lake, we found that the lake propagate the spirogyra extremely easily, a kind of filamentousalgae and its existent could influence the growth of the submerged plants. Therefore, we studied the spirogyra higher interference of the three submerged plants:Ceratophyllum demersum L., Myriophyllum spicatum L. and Hydrilla verticillata. Then we put the chosed submerged plants into a environment of Microcystis (Dominant algae in cyanobacteria bloom),and studied performance of the chosed submerged plants.The results provide the basic theory for the restoration of the aquatic vegetation in Dianchi lake. The main results are as follows:1. After the treatment of Spirogyra, compared with the control group, the biomass of Ceratophyllum demersum L. increased; in the21th days, chlorophyll content of the controls group was significantly higher than the treatment group, in the35th days and the41th days, chlorophyll content of control group decreased, and significantly lower than the treatment group (P<0.05); in the21th days, the superoxide anion content of the control group and the treatment group of were all increased and the control group was significantly higher than the treatment group, in the35th days the superoxide anion content in control group and the treatment group was no significant difference, in the41th days, the superoxide anion increased to maximum value, and the control group was significantly higher than the treatment group. The superoxide anion data of Myriophyllum spicatum L. was significantly higher than that of the control group, on the whole, the biomass data and chlorophyll content was significantly lower than the control group. After the treatment of Spirogyra, the superoxide anion content and Malondialdehyde (MDA) content of Hydrilla verticillata were significantly lower than that in the control group in the21th days, in the35th days were lower than or comparable to that of control group, in the41th days, the contents of the treatment group were significantly higher than the control group, indicating that Hydrilla verticillata itself in the regulation of metabolism to adapt to the changes of the environment, and the biomass and chlorophyll data performance for growth. Comparison of the three kinds of plant data, that is Hydrilla verticillata has certain anti-stress and the ability to adapt to the environment.2. After the treatment of Microcystis, the biomass of Hydrilla verticillata in the10th days and the20th days, was significantly higher than control group; the chlorophyll between the treatment group and the control group, had no significant difference, the content of superoxide anion showed that after co-culture, Hydrilla verticillata have the ability to adapt to the environment of cyanobacteria, after the addition of cyanobacteria, Hydrilla verticillata superoxide anion content increased, but after the second adding, the superoxide anion content changes are slowing down and in the20th day reached the minimum value of the experimental process. The MDA content between the treatment group and control group had no significant difference, there are differences of SOD activity in the5th days, and at other times had no significant difference, and the SOD activity all above the level of20U/g, relatively stable, that means with interference of cyanobacteria, Hydrilla verticillata can adapt to the harsh environment, and grow normally in environmental of cyanobacteria.