采用水培实验方法,研究了重金属Cr⁶⁺和除草剂乙草胺对少根紫萍(Spirodela oligorrhiza L.)生长的单一毒性和联合毒性效应。结果表明,Cr⁶⁺和乙草胺对少根紫萍96h生长抑制的IC₅₀分别为15.4和6.95mg·L^-1,在质量浓度1∶1的情况下,Cr⁶⁺与乙草胺共存对少根紫萍96h的IC₅₀为3.14mg·L^-1,二者为协同作用。随着Cr⁶⁺和乙草胺处理浓度的增加,少根紫萍叶绿素a浓度下降,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,还对少根紫萍生长抑制实验进行了探讨,建议使用植物个体数和重复间的偏差作为衡量实验质量的指标。

The single toxic and joint toxic effects of Cr⁶⁺ and acetochloron Spirodela oligorrhiza L. were studied. The results showed that the IC₅₀ of Cr⁶⁺ and acetochlor to S. oligorrhiza for 96 h were 15.4 and6.96 mg·L^-1 respectively, the IC₅₀of the joint toxicity of Cr⁶⁺-acetochlor for 96 h to S. oligorrhiza was 3.14 mg·L^-1 in concentration 1∶1. The additive index(AI) of Cr⁶⁺ and acetochlor was  0.28, the combined toxicities were the synergism action. With the increasing of the treatment concentration of Cr⁶⁺and acetochlor, the content of chlorophyll a decreased. The toxicity of combined pollution of Cr⁶⁺ and acetochloron S. oligorrhiza are obviously greater than those of single pollution, also being the synergism action. In addition, the quality control request of S. oligorrhiza growth inhibition test was discussed. It is suggested that the number of frond and the deviation of repeat are to be quality indexes of growth inhibition test of S. oligorrhiza.