Studying On Nitrogen Tolerance And Low-polluted Water Purification Of Ottelia Acuminata (Gagnep.)Dandy In Erhai Lake

Nowadays, ecological environment of Erhai is challenged by two serious problems, namely,pollution of low-polluted water and extinction in the wild of Ottelia acuminata (Gagnep.) Dandy.Relying on the National Erhai water special project of Chinese Twelfth Five Year Plan, afteranalyzing amounts of field survey date and hundreds of literatures, a series of simulatedexperimental were carried up. Then the change rules of indicators such as anti-oxidation enzymesystem and malondialdehyde (MDA) content in different experimental conditions were discussed,Ottelia acuminata (Gagnep.) Dandy’s adaptability and its purification rate of different kinds oflow-polluted water had also been studied. The hierarchical cluster analysis and the one wayANOVA analysis was used to determine the nitrogen tolerance on different substrates of Otteliaacuminata (Gagnep.) Dandy in its growth stages of seedling and adult. The results showed that:(1)the tolerance thresholds of ammonia nitrogen and nitrate nitrogen in water of Ottelia acuminata(Gagnep.) Dandy were determined successfully, and clarify the misunderstanding about whatOttelia acuminata (Gagnep.) Dandy is the absolute clear water macrophytes;(2) from suitablegrowth substrate, the optimal terrigenous substrate for Ottelia acuminata (Gagnep.) Dandy wasfound out;(3) the low-polluted water purification efficiency of Ottelia acuminata (Gagnep.)Dandy and its adaptability to4typical kinds of low-polluted water were discussed. Then the inletwater quality, purification rate of TN, TP and NH+4-N and hydraulic retention time parameters ofconstructed wetland which used for treat low-polluted water by using of Ottelia acuminata(Gagnep.) Dandy was measured. The dissertation’s achievements can provide basic data andscientific references for solving the above metioned two serious problems of Erhai Lake.