取食不同寄主棉蚜的羧酸酯酶和乙酰胆碱酯酶特性比较

以棉花、木槿和南瓜3种寄主作物隔离饲养不同抗性程度的棉蚜（171B、RR1和RR2），取食不同寄主后棉蚜羧酸酯酶的米氏常数（Km)值无显差异，而各品系之间酶的最大反应速度（Vmax)差异显。与取食棉花的棉蚜各品系相比，取食木槿的各品系乙酰胆碱酯酶对甲胺磷的敏感性均有所下降；取食南瓜的各品系以其抗性不同有所差异，抗性最高的RR2品系的敏感性上升，而RR1品系的敏感性有所下降，171B品系的敏感性无显性变化。在不同处理之间，棉蚜AChE的酶学特性（Km值和Vmax)也发生不同程度的改变，中对可能导致这种变化的原因进行了讨论分析。

Comparison of esterase and acetylcholinesterase of cotton aphid,Aphis gossypii Glover reared on different host plants

Three strains of cotton aphids,171B(susceptible),RR 1(medium resistant),RR 2(high resistant),were reared on cotton,hibiscus and pumpkin separately,and the esterase and acetylcholinesterase(AChE)were tested.For esterase,the similar K m showed that feeding on different host plants did not affect the composition of esterase isozymes of cotton aphids.However,the different V max indicated that host plants could cause some changes on esterase activity or quantity.For AChE,both K m and V max changed when the aphids were reared on different host plants.The K i tested indicated that feeding on hibiscus could make AChE of all strains less sensitive to methamidophos than those on cotton.But the sensitivity of AChE from aphid feeding on pumpkin varied with different strains.Aphids of 171B had the similar sensitivity to that feeding on cotton.The sensitivity of RR 1 increased and RR 2 was reduced.The possible causations of the changes in the esterase and AChE of cotton aphids are analysed.