The Effects Of Jasmonic Acid Induced And NPV Treat Populus Cathayana On Digestive Enzymes And PO Activity Of Lymantria Dispar

Populus cathayana is the main timber and garden greening tree species in the north of China, which often suffer frequent insects and diseases. The gypsy moth is one kind of insect pests. To study the impact of induced resistance of P. cathayana and nucleopolyhedrovirus (LdMNPV) on the activity of Phenoloxidase (PO) and midgut digestive enzyme of the3rd instar gypsy moth larvae by using jasmonic acid and virus. The results showed that:1Jasmonic acid induced resistance by P. cathayana and LdNPV both affected the3rd instar gypsy moth larvae hemolymph PO activity. Gypsy moth hemolymph PO activity rose with time which fed with the control, and it reached the maximum0.165U/(g.min) after96h. Hemolymph PO activity showed parabolic change which fed with the other3treatments. They all reached the maximum after72h, were0.163U/(g.min),0.173U/(g.min),0.155U/(g.min) respectively, higher than the control.2Jasmonic acid induced resistance by P. cathayana and LdNPV both inhibited the3rd instar gypsy moth larvae midgut PO activity. Gypsy moth larvae midgut PO activity assumed the trend of escalation which fed with CK, it reached the maximum0.464U/(g.min) after96h. Gypsy moth larvae midgut PO activity reached the maximum0.3U/(g.min) after96h which fed with JA. The PO activity increased first and then decreased after fed with the CK-N and JA-N, it was inhibited strongest after96h.3The effect of jasmonic acid induced P. cathayana resistance and NPV on the activity of the3rd instar gypsy moth larvae midgut protease was not significant. In96h, the protease activity of the control group was slight higher than the others.4The impact of jasmonic acid induced P. cathayana resistance and NPV on the activity of the3r instar gypsy moth larvae midgut amylase was significant. The activities of different treatments were significantly lower than that of the control; and the effect of inhibition increased gradually with time. The inhibition reached maximum after96h. The activity of CK-N, JA and JA-N were lower than the control, declined0.118mg/mg pro-min,0.448mg/mg pro-min,0.47mg/mg pro-min.5The midgut lipase activity of gypsy moth larvae fed with different treatment P. cathayana showed similar changes, which increased first and then decreased, and reached maximum after48h. The midgut lipase activity was inhibited strongest which fed with CK-N and JA after96h, declined0.062U·mL-1and0.1U-mL"1respectively compared with the CK. The midgut lipase activity reached the minimum which fed with the JA-N, was0.018U·mL-1.