黄曲条跳甲对毒死蜱敏感性差异的生化机制

Mechanism on susceptibility of striped flea beetle, Phyllotreta striolata to chlorpyrifos

采用生物测定方法测定黄曲条跳甲Phyllotreta striolata(F.)2个室内试验种群(蔊菜试验种群、上海青试验种群)和1个田间自然种群对毒死蜱的LC50值。结果表明,蔊菜试验种群对毒死蜱的LC50值最低,为30.3459mg.L-1;田间自然种群对毒死蜱的LC50值最高,为77.8448mg.L-1,与蔊菜试验种群相比的敏感性指数为0.39。对不同种群黄曲条跳甲乙酰胆碱酯酶(AChE)、羧酸酯酶(CarE)、谷胱甘肽-S-转移酶(GSTs)的活性测定结果表明,黄曲条跳甲田间自然种群AChE活性最低,与菜试验种群、上海青试验种群相比,差异极显著(P>0.01);田间自然种群GSTs活性最高,与蔊菜试验种群、上海青试验种群相比,差异极显著(P>0.01);黄曲条跳甲蔊菜试验种群CarE活性最低,田间自然种群CarE活性最高,二者差异极显著(P>0.01);说明黄曲条跳甲对毒死蜱的敏感性下降可能与AChE活性的降低,与CarE、GSTs的活性提高有一定的关系。

Bioassay was conducted to examine and compare LC50 values of a field natural population （FNP） and two laboratory population fed with Rorippa indica （RiP） and Brassica campestris （BcP） of striped flea beetle, Phyllotreta striolata（F.）, exposed to chlorpyrifos. The results indicated that LC50 value of RIP to chlorpyrifos was lowest with 30.3459mg·L^-1. while FNP the highest 77.8448mg·L^-1. The susceptibility index of FNP was 0.39. The enzymatic activities of acetylcholinesterase （ACHE）, carboxylesterase （CarE） and glutothine-transferase （GST） were measured to show difference of biochemical indexes of the SFB populations. The lowest AChE activity was observed in FNP, significantly different from those in RiP and BcP. The highest GST activity was found in FNP, while the lowest and highest CarE activities in RiP and FNP, respectively. Our study suggest that the susceptibility reduce of SFB to chlorpyrifos might be associated to some extent with lower ACHE, as well as higher activities of Care and GSTs.