Abstract Applying pesticides to crops is one of the causes of water pollution by surface runoff, and chlorpyrifos, trifluralin and chlorothalonil are used respectively as insecticide, herbicide and fungicide for crop plants widely. To explore effects of three pesticides on aquatic organisms, superoxide dismutase (SOD) and glutathione S-transferase (GST) activities were determined after 24 h and 48 h exposure of D. magna with ages of 6–24 h to several low concentrations of chlorpyrifos (0.36, 0.72, 1.43, 2.86, 5.72 μg∙L−1), trifluralin (0.17, 0.33, 0.66, 1.33, 2.65 mg∙L−1) and chlorothalonil (0.09, 0.18, 0.36, 0.72, 1.43 mg∙L−1) respectively. Main reproductive parameters including first pregnancy time, first brood time, the number of first brood and total fecundity after 21 d exposures at the same concentrations of pesticides as described above were also measured. The results showed that the activities of GST increased in lower concentrations and decreased in higher concentrations after 24 h exposure to three pesticides, respectively. The activities of SOD showed the same changes after 48 h exposure. With the time prolonged, the activities of GST decreased while the activities of SOD increased. After 21 d exposure, the first pregnancy time and first brood time were delayed, while the number of the first brood and total fecundity per female decreased with increasing concentrations. These results corroborated that GST activity was more sensitive to those pesticides than SOD activity, and there was a significant relationship between total fecundity and pesticides-dose(r>0.94, n=6), GST activity after 48 h exposure and total fecundity after 21 d exposure (r>0.92, n=6).

中文翻译：

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三种农药对大溞超氧化物歧化酶和谷胱甘肽-S-转移酶活性及繁殖的影响

摘要 对农作物施药是造成地表径流污染水体的原因之一，毒死蜱、氟乐灵和百菌清分别被广泛用作农作物的杀虫剂、除草剂和杀菌剂。为了探索三种农药对水生生物的影响，在 6-24 小时龄的大麦角藻暴露于几种低浓度毒死蜱 24 小时和 48 小时后测定了超氧化物歧化酶 (SOD) 和谷胱甘肽 S-转移酶 (GST) 活性(0.36, 0.72, 1.43, 2.86, 5.72 μg∙L−1)，氟乐灵 (0.17, 0.33, 0.66, 1.33, 2.65 mg∙L−1) 和百菌清 (0.09, 0.16, .2 mg∙L-1) 和 .3 mg∙L−1 1) 分别。主要繁殖参数包括首次怀孕时间、首次育雏时间、还测量了在上述相同浓度的农药下暴露 21 天后的初孵数量和总繁殖力。结果表明，暴露于三种农药 24 小时后，GST 的活性在较低浓度下增加，在较高浓度下减少。SOD 的活性在暴露 48 小时后显示出相同的变化。随着时间的延长，GST活性降低而SOD活性升高。暴露21 d后，首胎时间和首胎时间延迟，而随着浓度的增加，首胎数和每雌总产卵量减少。这些结果证实 GST 活性对这些农药比 SOD 活性更敏感，