镉急性染毒对中华稻蝗羧酸酯酶和谷胱甘肽S-转移酶活性的影响

为深入探讨重金属镉(cadmium,Cd)的毒性效应,采用不同浓度氯化镉溶液对中华稻蝗Oxya chinensis Thunberg 4龄若虫进行急性染毒,对处理后24、48、72和96 h虫体内羧酸酯酶(CarE)和谷胱甘肽S-转移酶(GST)活性进行测定。结果表明,随着处理时间的延长,对照组和处理组CarE和GST活性均表现为先升后降的趋势。与对照组相比,以α-NA为底物时高浓度处理组(80 mg.L-1)CarE活性在处理后48 h被激活;以β-NA为底物时中浓度处理组(40 mg.L-1)CarE活性在72 h达到最高;以CDNB为底物时,低浓度处理组(20 mg.L-1)GST活性在24 h被激活达到最大值,之后降低。结果显示,中华稻蝗4龄若虫在Cd胁迫下,体内CarE和GST活性发生了变化,以此来抵御机体所受到的重金属毒害。

Effects of Cd on carboxylesterase and glutathione S-transferase activity in Oxya chinensis

To illustrate the toxic effects of cadmium in Oxya chinensis Thunberg, levels of CarE and GST activity induced by acute exposure （24 , 48 , 72 , 96 h） to cadmium in forth-instar nymphs of O. chinensis were analyzed. The results show that the activity of both enzymes first increased then declined with exposure time in both control and treated plants. However, compared to control plants at the same treatment stage, CarE activity measured against 3-NA of treatments （80 mg L-1 ） was activated within 48 h, and the highest CarE activity measured against ct-NA of treatments （40 mg L-1 ） was observed within 72 h. The highest GST activity measured against CDNB of treatments （20 mg L-1 ） was observed within 24 h. These results indicate that CarE and GST activity in 0. chinensis changed in response to exposure to cadmium as part of a mechanism to protect plants against the toxic effects of this heavy metal.