氰氟草酯对泥鳅的毒性效应

Toxic Effects of Cyhalofop-butyl to Misgurnus anguillicaudatus

为检测除草剂氰氟草酯对水生生物的毒性效应,以泥鳅(Misgurnus anguillicaudatus)为受试对象,研究氰氟草酯对泥鳅的急性毒性、生理毒性、组织形态学毒性。急性毒性试验结果显示,氰氟草酯对泥鳅24、48、72、96 h的半数致死质量浓度(LC 50)分别为7.254 4、7.102 3、6.809 3、6.623 7 mg/L,安全质量浓度(SC)为2.042 3 mg/L。生理毒性试验结果显示,高质量浓度组(1.324 8 mg/L)氰氟草酯染毒1 d,泥鳅肝脏组织中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性最大,3 d时谷胱甘肽过氧化物酶(GSH-Px)活性最大;低质量浓度组(0.662 4 mg/L)氰氟草酯染毒7 d,SOD、CAT基因表达量最大,3 d时GSH-Px基因表达量最大,与对照(0 mg/L)相比差异显著。整体上,SOD、CAT、GSH-Px活性及其基因表达量随着染毒时间的延长和染毒剂量的增加呈现先上升后下降的趋势。组织形态学毒性试验结果显示,泥鳅暴露于低质量浓度(0.662 4 mg/L)氰氟草酯5 d时,出现肝脏细胞间隙变大现象,7 d时出现细胞肿大及细胞空泡化现象;暴露于高质量浓度(1.324 8 mg/L)1 d时,出现肝脏细胞间隙变大及细胞空泡化现象。随染毒时间的延长,细胞肿大及空泡化情况加深,同时出现核固缩现象。表明,氰氟草酯对泥鳅具有一定毒性,造成肝脏抗氧化酶系统和组织细胞的损伤,应适量科学施用。

In order to estimate the herbicide toxicity of cyhalofop-butyl to aquatic organisms,with Misgurnus anguillicaudatus as the experimental object,toxic effects of cyhalofop-butyl on Misgurnus anguillicaudatus including acute toxicity,physicological toxicity and histomorphological toxicity were studied.The results of acute toxicity test showed that the half lethal concentration(LC 50)of cyhalofop-butyl to Misgurnus anguillicaudatus in different periods(24 h,48 h,72 h and 96 h)were 7.254 4 mg/L,7.102 3 mg/L and 6.809 3 mg/L and 6.623 7 mg/L,respectively.The safety concentration(SC)was 2.042 3 mg/L.Through physiological toxicity experiments,the activities of SOD and CAT in Misgurnus anguillicaudatus’s liver increased obviously,and the maximum value appeared in the high concentration treatment group(1.324 8 mg/L)on the first day.The maximum activity value of GSH-Px appeared in the high concentration treatment group(1.324 8 mg/L)on the third day.Meanwhile,the maximum value of the expressions of SOD and CAT appeared in the low concentration treatment group(0.662 4 mg/L)on the seventh day.The expression of GSH-Px reached the maximum on the third day.And these had significant differences compared with the control(0 mg/L).Overall,with the extension of exposure time and the concentration increasing,the activities and gene expressions of SOD,CAT and GSH-Px initially increased and then decreased in the liver of Misgurnus anguillicaudatus.In the histomorphological toxicity test,the widened interstitial space could be observed in hepatocytes on the fifth day,while hepatocytes were swelling and more vacuolating on the seventh day in the low concentration treatment group(0.662 4 mg/L).Moreover,vacuolation was observed on the first day in the high concentration treatment group(1.324 8 mg/L).With the prolongation of exposure time,hepatocytes swelling and vacuolation deepened,and karyopyknosis could be observed.The experiment results showed that the cyhalofop-butyl had certain toxicity and damage effect on antioxidant enzyme system and histocyte of Misgurnus anguillicaudatus’liver,so it should be used reasonably and scientifically.