异小杆线虫对菜青虫体内保护酶活力的影响

测定了菜青虫(Pieris rapae)被异小杆线虫(Heterorhabditis megidis)侵染后体内主要保护酶活力的变化.结果表明:菜青虫感染昆虫病原线虫后,为抵御线虫对组织的破坏,菜青虫体内过氧化物酶(POD)活力在接虫初期迅速下降,之后不同接虫剂量处理的菜青虫体内的POD酶活力均有不同程度的上升,24h后逐渐降低;超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活力在接虫初期迅速上升,但在接虫后期均出现不同程度的下降,其中CAT酶活力在16h后达到最大,而POD的活力在8h达到最大之后逐渐减小.说明在菜青虫抵御病原线虫侵染的过程中,SOD和CAT是首先发生作用的保护酶,POD是继SOD和CAT之后发生作用的酶系,且反映出菜青虫在异小杆线虫侵染的初期防御能力增强,16～32h以后防御能力显著下降.

Changes of the activities of protective enzymes in Pieris rapae infected by Heterorhabditis megidis

The method of spectrophotometry was used to analyze the activities of endogenous enzymes of protective system in Pieris rapae which parasitized by Heterorhabditis megidis.The results showed that the activities of SOD,CAT and POD of Pieris rapae increased at the initial infected stage to resist the destruction of the organization of Pieris rapae infected by H.megidis,which decreased at the later infected stage.The highest activity of CAT occurred at 16 hour after inoculation,POD was at 8 hours,then the activity of POD declined seriously and decreased with the growing number of the H.megidis.The results suggested that SOD and CAT played important roles in defending against H.megidis and POD’s functions after them.The defense of Pieris rapae increased at the initial infected stage,but decreased sharply after 16 to 32 hours.