| Aquatic ecosystems is one of the most important ecosystems onthe planet. As the origin of life, bears many aquatic ecosystemsfunction. But now with the intensification of human activities, a largenumber of agro-industrial waste water and domestic sewage withoutproper treatment, or no treatment will be discharged into the riversand lakes, causing a large number of heavy metals, refractory materialaccumulated water body eutrophication frequent algal blooms haveoccurred when, to the landscape, water, safe drinking water caused aserious impact. Increasing the difficulty of flood control and thegeneral public on the relevant government departments pollutionfears.With the country in the12th Five Year Plan for "BeautifulChina"further interpretation of the CPC Central Committee’sdetermination to further strengthen the management of waterenvironment, governance around the water environment is constantlyadvancing. Shanghai, which work in this area at the forefront of thecountry, but many of the river after dredging, revetment remediation,ecological restoration of the river although transparency has beengreatly improved, but the emergence of filamentous algae (commonlyknown as moss) in a large number of broke out. Landscape effects on aquatic ecosystems, after a lot of corruption can easily affect waterquality, competitive water resources and limited light submergedplants, thereby affecting the aquatic ecosystem restoration effect. Andfilamentous algae outbreak due time is usually early spring (Februaryto April), a large eutrophic substances formed after the decay of theseason just as the summer heat a large outbreak of blue-green algaeblooms provide better material reserves had increased watereutrophication has an important contribution.For this reason, removal of filamentous algae water ecosystemsrestoration work has been one of the key and difficult. Filamentousalgae removal of the previous principal residence in removingchemicals, artificial salvage phases, but this work is not onlyinefficient, high maintenance cost to repair the water, and there is agreat risk of secondary contamination. For this to find a safe andpollution-free road becomes especially important.This study analyzed the filamentous algae habitats in which avariety of factors (abiotic factors: pH and heavy metals chromium andbiological factors: allelochemicals) impact on the growth,The resultsshow that, in the pH range of6.0to8.0, Spirogyra farlowii Transeaupresented certain resistance under the pH stress. While, when the pHstress exceeded the threshold level of8.5,the resistance of cells wouldbe weakened, resulting the growth inhibition, the damage on the cell structure, cell structure variation and mortality.Toxicity test of Cr6+result shows that the96hEC50of Cr6+toSpirogyra sp. is7.25mg·L-1. It has a significant positive correlationbetween electrical conductivity extracts form of cell with MDA（p＜0.05，r=0.891）. It has a significant positive correlation betweenelectrical conductivity extracts form of cell with Cr6+concentration（p＜0.05，r=0.951），and has a great significant positive correlationbetween MDAwith Cr6+concentration（p＜0.01，r=0.977）.Through its biomass (chlorophyll a), the environment shouldkinase (peroxidase POD, SOD superoxide dismutase and catalaseCAT), intracellular reactive substances (malondialdehyde MDA),membrane system integrity (cytoplasmic extravasation rate EL),photosynthetic rate (PSII maximum photochemical efficiency Fv/Fm,PSII actual photochemical efficiency ΦPS Ⅱ, the maximumefficiency of electron transfer rETRmax) submicroscopic structureand cell microstructure changes qualitatively and quantitativelyexplain the response to environmental stress; then continue to deleteselected experiments in which biological factors in different plants,allelochemicals the role of filamentous algae, evaluated several ofallelochemicals on aquatic ecosystems in other niche organisms(zooplankton Daphnia magna, zebrafish) toxicity, found some plantsallelochemicals extract has a certain role in the removal of targeted ecosystems and other low toxicity(The result shows that the extractsof all groups have inhibitory effect on Spirogyra after exposure for96h. The chlorophyll content of Spriogyra sp. cell decreased withincreasing of the extracts concentration, and showed meaningfuldose-effect relationship. The toxicity of T. dealbata extracts onSpriogyra sp. was more effective than O. sativa extracts (96hEC50T.dealbata6.85mg·L-1＜96hEC50O. sativa11.27mg·L-1）.There was asignificant positive correlation between content of MDA with theconcentration of Oryza sativa extracts（p＜0.05，r=0.907）, and therewas also a significant positive correlation between content of MDAwith the concentration of T. dealbata extract（sp＜0.01，r=0.891）. Theresults showed that the increase of membrane lipid peroxidation led tocellular structure damage and the increase of MDA content. Thecontents of MDA in T. dealbata treatments were higher than thecontent of MDA in O. sativa treatments in all extract concentrations.The maximum content of MDA reached1.884μmol·g-1in T. dealbataextracts (the extracts concentration is20mg·L-1) which was higherthan the contents of MDA concentration in O. sativa extracts by11.36%The result of Electrolyte leakage rate (EL) is consistent withMDA. The trend of maximal photochemical efficiency of PSⅡ(Fv/Fm)，the actual photochemical efficiency of PSⅡ in the light(ΦPSⅡ) and the maximal relative electron transport rate (rETRmax) of Spriogyra sp. have a significant negative correlation with theextract concentrations. ΦPSⅡ in treatment of Spriogyra sp. in extractof O. sativa decreased by96.74%, and it decreased by96.17%intreatment of Spirogyra sp. in the extract of T. dealbata. Fv/Fm intreatment of Spirogyra sp. in the extract of O. sativa decreased by96.58%, and it decreased by85.24%in treatment of Spirogyra sp. inthe extract of T. dealbata. rETRmax in treatment of Spirogyra sp. inthe extract of O. sativa decreased by84.56%,and it decreased by43.30%in treatment of Spirogyra sp. in the extract of T. dealbata.).And conducted a brief extract allelochemicals extraction andseparation experiments in the hope that future work can be identifieddeeply isolated extract, separation, purification, etc.; under light andelectron microscopy to identify some of allelochemicals extractedmatter on filamentous algae cells may attack targets.Through the above work, the author hopes to be able to find anecological, safe, efficient, long-lasting roads and filamentous algaeremoval approch. |
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