【摘要】 不同虫龄小菜蛾对抑太保的敏感性差异较大 ,其中 4龄是 1龄的 1 1 .6倍 .不同温度下抑太保对 3龄幼虫的 LC50 随温度的升高而迅速下降 ,1 0℃时为 1 2 43 .94mg·L- 1 ,3 5℃时则下降到 5 .0 6mg·L- 1 .酰胺酶的米氏常数 (Km)为 3 .65× 1 0 - 5nmol,最大反应速度 (Vm ax)为 0 .1 465 nmol· mg- 1 ·min- 1 .4龄幼虫酰胺酶的比活力和总活力随温度的升高而增大 .4℃饲养 1 5 d、1 0℃饲养 1 0 d及 2 5℃饲养条件下 ,4龄幼虫酰胺酶的比活力差异不大 ;但 3 5℃饲养 2 d与前 3个饲养条件相比 ,4龄幼虫酰胺酶的比活力差异较大 .酰胺酶的比活力和总活力均随虫龄的增长而增大 ,4龄与 1 -3龄相比酰胺酶的比活力差异较大 ,不同虫龄酰胺酶的总活力差异显著更多还原

【Abstract】 The experiment showed that the sensitivity of different instars of diamondback moth Plutella xylostella (L.) to chlorfluazuron varied significantly. The ratio was 11.6 folds according to comparison of the LC 50 of the fourth instar larvae with the first instar. The test of the toxicity of the third instar showed significant difference under different temperatures. With the rise of temperature, the LC 50 sharply decreased to 1 243.94 mg·L -1 at 10 ℃, and continued to drop to 5.06 mg·L -1 at 35 ℃. K m and V max of amidase were 3.65×10 -5 nmol·L -1 and 0.1465 nmol·mg -1 ·min -1 respectively. When the temperature rose, the amidase specific activity and total activity of the fourth instar increased accordingly. After fed at 4 ℃ for 15 days, 10 ℃ for 10 days and 25 ℃ respectively, and at 35 ℃ for 2 days, by testing the enzyme activity of the fourth instar, the enzyme specific activity at 4, 10 and 25 ℃ showed little difference, at 35 ℃, however, it differed greatly from those former three. As the instar developed, the amidase specific activity and total activity also amplified accordingly, the specific activity of the fourth instar showed significant difference compared with those from first instar to third instar, and the total activity in different instars also showed great difference.更多还原