镉和乙草胺对少根紫萍的毒性效应

联合毒性实验在水环境污染评价中非常重要.本文以少根紫萍(Spirodela Oligorrhiza)为研究对象,研究了重金属Cd和除草剂乙草胺对少根紫萍生长的单一毒性和联合毒性效应.实验结果表明:Cd、乙草胺及对少根紫萍的96h-IC50分别为4.77mg/L和6.95mg/L,在浓度1:1的情况下,Cd与乙草胺共存对少根紫萍的96h-IC50为1.41mg/L,采用Marking相加指数法求得相加指数AI为1.00,大于零,为协同作用.同时,随着Cd、乙草胺处理浓度的增加,少根紫萍叶绿素a的浓度下降,其中Cd对叶绿素a的影响大于乙草胺,复合污染对叶绿素a的影响明显大于单一污染,也表现为协同作用.另外,本文还对少根紫萍生长抑制试验进行了探讨,建议使用植物体数和重复间的偏差作为衡量试验质量的指标.

Toxic effect of cadmium and acetochlor on Spirodela Oligorrhiza

The present paper aims to study the single toxic effects and the joint toxic effects of Cadmium and Acetochlor in Spirodela Oligorrhiza. Our experimental results have shown that the IC_(50) of two-valence Cadmium and Acetochlor to Spirodela Oligorrhiza were 4.77 mg/L, 6.96 mg/L, the IC_(50)of the joint toxicity of Cadmium and Acetochlor to Spirodela Oligorrhiza was 1.41 mg/L. In accordance with the additive index method of Marking, the additive index (AI) is 1.00. It is greater than zero. The combined toxicities may produce synergism actions. At the same time, with the increase of the treatment concentration of Cadmium and Acetochlor, the content of chlorophyll a would decrease while the effect of Cadmium on the concentration of chlorophyll a would be higher than Acetochlor. Therefore, it would be clear that the effects of the combined pollution would be heavier than those of single pollution. The results have also shown the synergistic action. In addition, the paper has also discussed the quality control demands of Spirodela Oligorrhiza growth inhibition test. In this connection, it is also suggested to make frond and deviation of repetition the index of Spirodela Oligorrhiza growth inhibition test quality, in which Spirodela Oligorrhiza individual should be young, breed fast, sensitive to the pollutant for it to be a kind of good toxicology material.