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研究报告

Effects of different light intensities on the toxicities of atrazine and paraquat to algae

基金项目：环保部环保公益性行业科研专项经费（No.210009033）；国家自然科学基金（No.31370217）；江苏省优势学科建设工程项目；国家基础科学人才培养基金（No.J1103507）

摘要：分别在20和50 μmol·m^-2·s^-1光照强度下，研究了两种除草剂阿特拉津和百草枯对3株蓝藻：铜绿微囊藻Microcystis aeruginosa PCC7806、M. aeruginosa XW01、集胞藻Synechocystis PCC6803和两株绿藻：蛋白核小球藻Chlorella pyrenoidosa、四尾柵藻Scenedesmus quadricauda的毒害效应.通过测定藻的生长，计算出了半效抑制浓度EC₅₀值，结果表明：高光强下两种除草剂对5株藻的96 h-EC₅₀值均明显低于低光强下的值，显示高光强有促进两种除草剂对藻类毒害的效应.高光强可促使阿特拉津显著提高藻细胞的丙二醛（MDA）含量，提示高光强促进阿特拉津产生更多的自由基破坏细胞膜脂.

Abstract：To investigate the effect of light on the toxicity, two light intensities, 20 and 50 μmol·m^-2·s^-1 were used for testing the toxicities of atrazine and paraquat to three Cyanophyta strains (Microcystis aeruginosa PCC7806, M. aeruginosa XW01 and Synechocystis PCC6803) and two green algae (Chlorella pyrenoidosa and Scenedesmus quadricauda). The EC₅₀ (Median Effect Concentration) was calculated by algal growth in different concentrations of atrazine and paraquat. The experimental results showed that the 96 h-EC₅₀ values of five test strains under stronger light were significantly lower than those under weaker light, and higher light intensity could increase the toxicities of atrazine and paraquat to algae. The malondialdehyde (MDA) contents of the algae caused by the atrazine significantly rised under higher light intensity, since atrazine could produce more radicals to destroy the membrane lipids under higher light.