苯嗪草酮对2种淡水水生植物的生长抑制影响

为评价苯嗪草酮施用后的水生生态安全性,研究苯嗪草酮对小浮萍和穗状狐尾藻的生长抑制影响及其毒性效应。用不同质量浓度的苯嗪草酮对小浮萍和穗状狐尾藻进行暴露处理,以叶状体数和鲜重,植株长度和鲜重为分析指标,分别在第7天和第14天进行观察测定。结果表明：7天小浮萍E_rC₅₀和E_yC₅₀的叶状体数为0.519、0.322 mg/L,鲜重分别为0.518、0.328 mg/L;14天穗状狐尾藻E_rC₅₀和E_yC₅₀的植株长度为6.240、4.248 mg/L,鲜重分别为4.092、2.616 mg/L。苯嗪草酮对小浮萍和穗状狐尾藻具有一定的毒性,抑制其生长。在一定的剂量范围内,抑制率随浓度的增加而增大。但是,苯嗪草酮对两者的毒性作用表现出明显的分类学效应。

Metamitron: Growth Inhibition on 2 Freshwater Aquatic Plants

To evaluate the aquatic ecological safety of metamitron application, the growth inhibition and toxicity of metamitron on Lemna minor and Myriophyllum spicatum were studied. The number of lobes, fresh weight, plant length and fresh weight were taken as the analysis indexes and the measurement was conducted on the 7 ^th and 14^th day after the exposure treatment under different concentrations of metamitron. The results showed that: E_rC₅₀ and E_yC₅₀ of Lemna minor was 0.519 mg/L and 0.322 mg/L on lobes and 0.518 mg/L and 0.328 mg/L on fresh weight respectively on the 7 ^th day, while that of Myriophyllum spicatum was 6.240 mg/L and 4.248 mg/L on plant length and 4.092 mg/L and 2.616 mg/L on fresh weight respectively on the 14 ^th day. Metamitron had certain toxicity on Lemna minor and Myriophyllum spicatum, and inhibited their growth. In conclusion, the inhibition rate increases with the increase of metamitron concentration in a certain dose range; however, metamitron shows significant taxonomic effects on Lemna minor and Myriophyllum spicatum.