问题描述：
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,不少有机化合物可以通过自然界本身物理的、化学的或生物的净化,使有害性降低或解除.而重金属具有富集性,很难在环境中降解.
所以研究重金属污染是非常必要的,而研究重金属水污染对水生植物的毒害机理更具有现实意义.因为在人类活动中产生的污染物质无论来自大气,还是来自土壤,将最终归为水污染.而水体重金属污染直接影响水生植物的正常生长发育,进而影响生态系统和人类健康.
为了研究重金属污染对水环境生态的影响,本文通过将新鲜的菹草暴露于不同重金属(Cu2+、Cd2+和Pb2+)的不同浓度（0、0.1、0.2、0.5和1.0mg/L）中进行不同时间（t=0、t=4h、t=28h）重金属胁迫的性能研究,利用水下调制荧光仪测定菹草的叶绿素荧光参数,共取得了45组（每组三个平行）、135次数据.由实验数据得知,随着重金属离子浓度的增加,相对光合电子传递速率（ETR）、最大光化学量子产量（Fv/Fm）、光化学淬灭系数（qP）以及实际量子产量（Yield）等荧光参数均逐渐降低,而非化学淬灭系数（NPQ）逐渐上升.研究结果表明：重金属离子对菹草的光合作用具有一定的抑制性,其机理可能为通过引起PSⅡ系统反应中心的部分失活,导致PSⅡ系统反应中心的开放比例减少,从而引起电子传递速率的降低,使光合速率下降.且重金属离子浓度越高,PSⅡ系统反应中心被破坏的越严重.
本文通过对不同重金属胁迫时对菹草叶绿素荧光特性的研究与探究,为进一步了解重金属的生态毒性效应提供参考,通过不同重金属对水生植物的短期毒害性研究,评估重金属对水生生态系统的风险和危害提供参考.
关键词：重金属；水污染；菹草 ；叶绿素；荧光参数
问题解答：
我来补答
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
