有机磷农药敌敌畏对赤潮异弯藻（Heterosigma akashiwo）的毒物刺激效应

研究了敌敌畏（0.001、0.01、0.1、1、10mg·L-1）对赤潮异弯藻（Heterosigma akashiwo）生长、叶绿素a、类胡萝卜素、可溶性蛋白、超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性的影响。结果表明,在0.001、0.01、0.1mg·L-1三个质量浓度处理下,微藻第3~5d的相对增长率显著高于对照组。1和10mg·L-1质量浓度处理下,最初微藻增长受抑制,培养7d后出现补偿增长现象。在0.01和0.1mg·L-1敌敌畏质量浓度下,叶绿素a含量和对照相比分别提高了5.9%和5.2%,类胡萝卜素含量分别比对照组提高了9.0%和11.2%。96h可溶性蛋白含量分别比对照组提高了7.1%和15.3%。和对照组相比,SOD和CAT在24h时主要受抑制作用,48h时SOD活性恢复,趋于和对照组一致,而CAT活性受到强烈诱导。结果显示当敌敌畏浓度低于0.1mg·L-1时,对赤潮异弯藻主要表现刺激生长作用,而当浓度超过1mg·L-1时,主要表现抑制作用。

Hormesis effect of organophosphorus pesticide dichlorvos on harmful algal bloom specie Heterosigma akashiwo

The effects of dichlorvos（0.001,0.01,0.1,1,10 mg·L -1 ）on the growth activities were studied by the term of chlorophyll-a,carotenoids,protein,and of two antioxidant enzymes（SOD and CAT）of Heterosigma akashiwo.The results indicated that under the concentrations from 0.001 mg·L -1 to 0.1 mg·L -1 ,the relative growth rates of Heterosigma akashiwo at 3-5 days were obvious higher than those with control treatment.While,at the concentration of 1 mg·L -1 and 10 mg·L -1 ,the growth rates were inhibited initially and then enhanced significantly after 7 days compared with control treatment.However,comparing with the control,under the concentrations of 0.01 mg·L -1 and 0.1 mg·L -1 ,the content of chlorophyll-a by 5.9%and 5.2%,the carotenoids by 9.0%and 11.2%, the protein by 7.1%and 15.3%were increased at 96 h,respectively.The activities of SOD and CAT were both inhibited by dichlor- vos at various concentration of 0.01,0.1,1 and 10 mg·L -1 at 24 h,while at 48 h the activity of SOD was recovering almost identical with the control,and the activity of CAT was significantly increased.The result indicated that when the concentration was below 0.1 mg·L -1 ,dichlorvos show hormesis effect,while the concentration was above 1 mg·L -1 ,the inhibition effect was observed.