枸杞蚜虫羧酸酯酶特性及杀虫剂对其的抑制作用

CHARACTER OF CARBOXYLESTERASE AND EFFECT OF INSECTICIDES TO CARE IN Aphis SP.

枸杞蚜虫是危害枸杞产量和质量的重要害虫。本文采用药膜法测定了4种杀虫剂对枸杞蚜虫的毒力,同时采用分光光度法测定了枸杞蚜虫羧酸酯酶(Car E)的特性和杀虫剂对其的抑制作用。结果表明,灭多威对枸杞蚜虫的毒力最大,LC50为0.640mg/L;氧化乐果毒力最小,LC50为18.783mg/L;异丙威和三唑磷居中,LC50分别为6.696mg/L和8.201mg/L。α-乙酸萘酯为枸杞蚜虫羧酸酯酶的最适底物,以α-乙酸萘酯为底物反应的Km值为0.050 3±0.004 27μmol/L,Vmax值为0.950 7±0.020 8μmol/min·mg。4种杀虫剂对枸杞蚜虫羧酸酯酶(Car E)体外抑制结果表明,2种有机磷杀虫剂对Car E的抑制大于两种氨基甲酸酯类杀虫剂。三唑磷和氧化乐果抑制中浓度(I50)分别为0.629 5×10-5mol/L和0.150 7×10-3mol/L,异丙威和灭多威抑制中浓度(I50)为0.229 6×10-3mol/L和1.023×10-3mol/L。同时,4种抑制剂对枸杞蚜虫羧酸酯酶抑制的时间动力学曲线不同,其中三唑磷、氧乐果、灭多威比较相似,在2min内抑制率可达60%以上,之后缓慢增加;异丙威在2-10min内,抑制率由10%增加到60%,之后增加速度趋缓。

Aphis sp. is one of the major pest of the wolfberry,and causes a horrible threat to the yield and quality of wolfberry in long-term. The method of the residual film in glass tube was employed for determining toxicities of insecticides. In the same time,it was studied too that substrate specificity of carboxylesterase and the inhibition of insecticides to Aphis sp.. The results showed that Aphis sp. was the most sensitive to methomyl in the insecticides tested,and LC50 of methomyl was 0.640 mg / L,while the least sensitive to omethoate,and LC50 of omethoate was 18.783 mg / L,the LC50 values of isoprocarb and triazophos respectively were 6.696 mg /L and 8.201 mg / L. The α-NA was the optimum substrate. Km was 0.050 3±0.004 27μmol / L,and Vmax was 0.950 7±0.020 8μmol /min·mg. It was shown that the activity of Car E in Aphis sp. could be significantly inhibited by four insecticides. Inhibition of organophosphate insecticides on Car E was greater than that of the carbamate insecticides. The values of I50 of triazophos and omethoate to Car E were 0.629 5×10^-5mol / L and 0.150 7×10^-3mol / L. The values of I50 of isoprocarb and methomyl to Car E were 0. 229 6 ×10^-3mol / L and 1. 023 ×10^-3mol / L. Further on,the time kinetic curves of 4 insecticides of inhibitors on inhibition of Car E in Aphis sp. were different. The inhibition rates of three insecticides were above 60% in 2 minutes,and then increased slowly; but the inhibition rate of isoprocarb increased with reaction time. Between 2 and10 minutes,the inhibition rate increased from 10%to 60%.