镉与S-异丙甲草胺对斜生栅藻的联合毒性作用

采用毒性标准实验方法研究了Cd2+与S-异丙甲草胺单独及联合作用对斜生栅藻急性毒性、总可溶性蛋白含量、超氧化物歧化酶(SOD)活性和细胞膜通透性的影响.结果表明Cd2+与S-异丙甲草胺单独作用时EC50均随时间的延长而减小,且S-异丙甲草胺的急性毒性大于Cd2+;Cd2+、S-异丙甲草胺的EC50-24h分别为0.27 mg·L-1、0.24 mg·L-1,EC50-96h分别为0.16mg·L-1、0.13 mg·L-1.Cd2+与S-异丙甲草胺联合作用时低浓度表现为协同作用,高浓度表现为拮抗作用.暴露96 h后,Cd2+与S-异丙甲草胺单独及联合作用下,随有毒物质浓度升高,斜生栅藻总可溶性蛋白含量降低,SOD酶活性先激活后抑制,细胞膜通透性逐渐增大.

Combined Toxicity of Cadmium and S-metolachlor to Scenedesmus obliquus

The single and combined effects of Cd²⁺ and S-metolachlor on acute toxicity, total soluble protein content, superoxide dismutase (SOD) activity and cell membrane permeability of Scenedesmus obliquus (S. obliquus) were studied using the standard toxic testing methods. The results showed that the EC₅₀ of Cd²⁺ and S-metolachlor decreased with time, and the acute toxicity of S-metolachlor was higher than that of Cd²⁺, EC_50-24h of Cd²⁺ and S-metolachlor was 0.27 mg·L^-1 and 0.24 mg·L^-1, respectively, and EC_50-96h was 0.16 mg·L^-1 and 0.13 mg·L^-1, respectively. The combined toxicity of Cd²⁺ and S-metolachlor showed a synergistic effects at low concentration, and antagonism effects at high concentration. After 96h-exposure, the total soluble protein content of S. obliquus decreased, the SOD activity first increased and then decreased, and the cell membrane permeability increased with the increasing concentration of both single and combined treatment.