有机磷农药草甘膦异丙胺盐对赤潮异弯藻的毒物干扰效应

Hormesis effect of organophosphorus pesticide glyphosate-isopropylammonium on Heterosigma akashiwo

以我国典型赤潮藻赤潮异弯藻(Heterosigma akashiwo)为研究对象,设置了6个浓度梯度(0 mg.L-1、0.001mg.L-1、0.01 mg.L-1、0.1 mg.L-1、1 mg.L-1和10 mg.L-1)的草甘膦异丙胺盐处理,研究了草甘膦异丙胺盐暴露对赤潮异弯藻的生长、叶绿素a含量和可溶性蛋白含量等指标的影响。结果表明,草甘膦异丙胺盐对赤潮异弯藻具有明显的毒性效应,10 mg.L-1浓度处理下,赤潮异弯藻细胞大量死亡,藻细胞密度以及叶绿素a、可溶性蛋白的含量显著降低(p<0.05);当草甘膦异丙胺盐浓度在0.001～1 mg.L-1范围内,在培养的第3 d草甘膦异丙胺盐能够显著促进赤潮异弯藻的细胞密度增加,叶绿素a含量也明显高于对照组(p<0.05),表现出毒物刺激效应;在暴露实验的中后期(第7 d、第9 d和第11 d),赤潮异弯藻的各生长指标均与对照无显著差异,可能是随着培养时间的延长,农药的降解、生物体对农药的适应、进入细胞的农药减少等原因,藻细胞生理状态逐渐恢复到正常水平。

The growth, chlorophyll a contents, protein contents of Heterosigma akashiwo under different concentrations of glyphosate-isopropylammoninm （0, 0.001, 0.01, 0.1, 1 and 10 mg-L-l） were investigated. The results showed that glyphosate-isopropylammonium caused significantly toxic effect on microalgae. The cell density, chlorophyll a contents and protein contents were decreased significantly under 10 mg.L-1 concentration（p〈0.05）. Low dose of glyphosate-isopropylammonium had significantly stimulated effect on microalgae. The growth and chlorophyll a contents of H. akashiwo were significantly increased as compared to the control group under low concentrations （〈 1 mg-L-l） at 72 h （p〈0.05）. At latter period of the experiment （7th, 9th, 11 th day）, the stimulated effect gradually disappeared, with no significant difference in physiological characteristics between treatments and the control group.