英语翻译水环境污染已成为当今世界面临的问题之一,而重金属水污染显得更为突出.重金属污染与其他有机化合物的污染不同,不少有

Water pollution has become one of the problems facing the world today,and the heavy metal pollution becoming more and more prominent。Heavy metal pollution and other organic compounds pollution are different,a lot of organic compounds can be made by nature itself physical,chemical or biological purification,so that harmful to reduce or cancel。While the heavy metal enrichment,it is difficult to degrade in the environment。So the study of heavy metal pollution is very necessary,and the study of heavy metal pollution on aquatic plant poison mechanism has more realistic significance。Because in the human activity of contaminated material from the atmosphere,or from the soil,will eventually return to water pollution。The heavy metal pollution of water body directly influence the aquatic plant growth and development,thereby affecting the ecosystem and human health。In order to study of heavy metal pollution on water environment and ecological effect,this article through the fresh crispus exposed to different heavy metals ( Cu2 +,Cd2 + and Pb2 + ) of different concentrations (0,0。1,0。2,0。5 and 1。0mg / L ) in different time ( t = 0,t =4h,t =28h ) heavy metal stress performance research,using underwater modulated fluorescence determination of chlorophyll fluorescence parameters of Potamogeton crispus,made a total of45 groups ( n = three in parallel,135 data )。The test results indicate that,with the increase of the relative concentration of heavy metal ion,photosynthetic electron transport rate ( ETR ),maximal photochemical quantum yield ( Fv / Fm ),photochemical quenching coefficient ( qP ) as well as the actual quantum yield ( Yield ) and fluorescence parameters were gradually reduced,but not chemical quenching coefficient ( NPQ ) rises gradually。The results show that:heavy metal ion of Potamogeton crispus photosynthesis has certain inhibition,its mechanism may be induced by PS II reaction center partial inactivation,leading to PS II reaction center opening ratio is reduced,thereby causing the electron transfer rate is reduced,so that the decline in photosynthetic rate。And the higher the concentration of heavy metal ion,PS II reaction center was destroyed by the more serious。This article through to the different heavy metal stress on chlorophyll fluorescence characteristics of Potamogeton crispus and inquiry,in order to further understand the heavy metal ecological toxicity of heavy metals to provide reference,through different aquatic plants short-term toxicity studies,assessment of heavy metals in aquatic ecosystems and the risk of harm to provide reference。Provide reference。Key words:water pollution; heavy metals; effect; chlorophyll; fluorescence parameters个别句中可能语法会有一点点的出入