| Elodea Canadensis Michx. is a kind of submerged macrophyte originally grown in America, Because of its high growth speed and great adaptation to the environment, it is widely used in the field of water protection and aquaculture. The thesis aims to test its ability of rehabilitating destroyed water ecosystem. The experiment proves:(1) Elodea Canadensis Michx. can highly purify water, effectively eliminate nitrogen, phosphorus and other organic substances, increase transparency, restrain the growth of phytoplankton in water. In this way, it improves the water quality.(2) The change of seasons has a great influence on the growth of Elodea Canadensis Michx. and the content of Chlorophyll. Its Net production of oxygen is in proportion to Chl.a/ Chl.b, and its Gross production of oxygen is in proportion to the content of Chl.b.(3) When Elodea Canadensis Michx. is in its midseason (spring and summer), the number of bacteria in its growth environment is big; while in its off-season, the number of bacteria is small.(4) Temperature, sunlight, and pH are closely related to the photosynthesis of Elodea Canadensis Michx.. The former two have curve correlation with production of oxygen in the photosynthesis of Elodea Canadensis Michx. When pH is from 5 to 10, the photosynthesis of Elodea Canadensis Michx. is inversely proportional to pH. The optimal growth environment for Elodea Canadensis Michx. is neutral or sub acid, 10 to 25 ℃ , and 4× 104lx6× 104lx.(5) The density of periphytic algae and amount of living things on the surface of Elodea Canadensis Michx. is inversely proportional to the growth of Elodea Canadensis Michx. Periphytic algae restrain the growth and distribution of Elodea Canadensis Michx.(6) Bi-pollution will emerge during the process of Elodea Canadensis Michx. planting. Especially when it decomposes, nutritive material released will greatly influence TN, TP and CODMn.In general, Elodea Canadensis Michx. can normally grow in plain area. It is one of the most important plants which can rehabilitate destroyed water ecosystem. The author also carried out applied research on Elodea Canadensis Michx.'s ability of rehabilitating destroyed water ecosystem, and discussed its application foreground and application mode. It turns out that Elodea Canadensis Michx. is easy to plant on a large scale and of certain economic value. It is the ideal material for rehabilitation of submerged macrophyte in destroyed water ecosystem. |
