Study On The Effect Of Adjuvant On The Biological Toxicity Of Algae Chlorophyll Fluorescence To Herbicides

Heavy use of herbicides causes serious environmental problems.The rapid detection of the biological toxicity of residual herbicides in the water environment is of great significance for evaluating the environmental effectiveness of herbicides.Algae chlorophyll fluorescence has a sensitive response to herbicides.In order to establish a rapid and sensitive method for detecting algae biotoxicity by algae fluorescence,this experiment investigated the biotoxic response mechanism of algae fluorescence to herbicides(triazine herbicides)under ammonium sulfate adjuvant.Two sensitive algal species,Chlorella pyrenoidosa and Scenedesmus obliquus were selected as indicator algae.The photosynthesis inhibitors triazine herbicide of atrazine and ametryn were used as test herbicides.Chlorophyll fluorescence parameter of maximum photosynthesis eff-iciency(Fv:Fm)was applied as a parameter index to analyze the biological toxicity of the herbicide.The experimental results showed that the adjuvant ammonium sulfate could obviously promote the algae fluorescence biological toxicity experiment of the herbicide.Furthermore,the optimal test environment was researched,including the optimal test time,adjuvant concentration,temperature and pH.At the same time,bentazon(phenothiazine)was selected as test herbicide,which further verified that ammonium sulfate had a significant effect on the algal fluorescence biotoxicity of herbicides.The test algae were cultured,and it was determined that the logarithmic cycle of Chlorella pyrenoidosa began on day 6,and the logarithmic cycle of Scenedesmus obliquus began on day 7.The optimal response time of both Chlorella pyrenoidosa and Scenedesmus obliquus was 6 mins under atrazine and ametryn stress respectively.The optimal response time of Chlorella pyrenoidosa nucleus under the effect of bentazon was 50 mins,while the optimal response time of Scenedesmus obliquus under the pressure of bentazon was 10 mins.The optimal detection environment for atrazine herbicide-stressed microalgae:the optimal concentration of ammonium sulfate for both algae was 1 ?g·L-1,and the optimal reaction temperature was 40?;The best reaction pH of Chlorella pyrenoidosa was 11,and the optimal reaction pH of Scenedesmus obliquus was 3.The best detection environment for the microalgae under the ametryn of herbicides:the concentration of ammonium sulfate,the best adjuvant for both algae,was 1 ?g·L-1,and the optimal reaction temperature was 40?;The optimal reaction pH of Chlorella pyrenoidosa was 11 and the optimal reaction pH of Scenedesmus obliquus was 3.The optimal monitoring environment for Scenedesmus obliquus under stress of bentazon:the optimal concentration of the adjuvant was 5 ?g·L-1,and the optimal reaction temperature was 40?,and the optimal reaction pH was 3.The sensitive algae of atrazine herbicide was Scenedesmus obliquus,and the sensitive algae of ametryn herbicide was Chlorella pyrenoidosa,and the sensitive algae of herbicide bentazon was Scenedesmus obliquus.It was proved that the use of ammonium sulfate adjuvant could improve the response performance of algae fluorescence to herbicides and provide data support for the establishment of rapid field screening methods.