氯氰菊酯对锥状斯氏藻的毒性效应

Toxic effects of cypermethrin on Scrippsiella trochoidea

为了评估拟除虫菊酯农药对海洋生物以及海洋环境的毒性效应，研究了氯氰菊酯对锥状斯氏藻（Scrippsiella trochoidea）的毒性效应及其对叶绿素a（Chl.a）、可溶性糖、可溶性蛋白含量以及超氧化物歧化酶（SOD）活性、丙二醛（MDA）含量等生理生化指标的影响。结果表明，低浓度（≤10μg·L^-1）的氯氰菊酯对锥状斯氏藻生长具有明显的促进作用，而高于50μg·L^-1则产生较明显的抑制效应。藻细胞所有生理生化指标在暴露初期的6～12h较为敏感，24h或48h后趋于平稳；细胞内含物包括Chl.a、可溶性糖、可溶性蛋白含量以及SOD活性，在低浓度时均出现诱导现象，而高浓度时则呈现先抑制后恢复的现象。而氯氰菊酯对藻体内MDA含量均具有促进作用，浓度越高促进作用越强。研究结果表明，锥状斯氏藻的各种生化指标对氯氰菊酯的响应均较为敏感，但SOD和MDA对剂量反应更为敏感，最低影响剂量为5μg·L^-1和1μg·L^-1，可作为拟除虫菊酯农药污染早期预警的生物指示指标。

In order to assess the toxic effects ofpyrethroid pesticides to marine environments, the toxicity of cypermethrin on the growth ofScrippsiella trochoidea and biochemical parameters including contents of chlorophyU a （Chl. a）, soluble sugar, soluble protein, malondialdehyde （MDA） and activity of superoxide dismutase superoxide dismutase （SOD） were studied. Results showed that cypermethrin accelerated the growth of S. trochoidea obviously at concentration below 10μg·L^-1, but inhibited the growth significantly when concentrations were over 50 μg·L^-1. All of the biochemical parameters were sensitive at the early 6-12 h exposure stages, and became to be stable after 24 h or 48 h exposure. The contents of Chl. a, soluble sugar, soluble protein and the activity of SOD were induced at lower concentrations, and were initially inhibited and then recovered at high concentrations. However, MDA content increased significantly with the increasing of concentrations. The results indicated that all biochemical indicators of S. trochoidea measured in this study were sensitive to cypermethrin. Furthermore SOD and MDA were more sensitive, with the minimum effective concentration of 1 μg·L^-1 and 10μg·L^-1, respectively, which suggested that both SOD and MDA might be capable to be used as biomarks for the early warning of pyrethroid pesticide contamination.