Studies On The Activities Of Protective Enzyme Of Pieris Rapae And Tenebrio Molitor L. Infected By Two Kinds Of Entomopathogenic Nematodes Of Gansu Province

The stress response of organism which is related to the strength of the size of duress and the size of the organism itself is a kind of resistance to exotic duress. Oxidative stress is a kind of stress response often encountered by the body of organism.Three kinds of enzymes which are superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) known as the protective enzyme system coordinating make free radicals stay at a low level so that prevent the free radicals from poison.Aiming at exploring controlling potential of Entomopathogenic nematodes (EPN) of Gansu province, two fine quality strains (0627M strain of Heterorhabditis megidis and 0619HT strain of Steinernema feitiae) were studied on the 4th instar of Pieris rapae and Tenebrio molitor were infected by S. feitiae. SOD, POD and CAT activities of the infected P. rapae and T. molitor were detected at different times. The results are as follows:There was a positive correlation between SOD, POD, CAT activities and the doses of EPN. After applying EPN to the P. rapae and T. molitor, the levels of SOD, POD and CAT activities were found to sore gradually and be higher than those of the unontrol. The more the quantities of the EPN, the greater the increase,it suggestsd that the organism itself can improve protective enzyme activities so that it can adapt to the impact of the outside world. The protective enzyme activities began to decline rapidly after 16-24hs and the more doses of EPN, the quicker it declined.These protective enzymes activities of the infected pests were related to the treated time. At first, protective enzyme activities were on upward trend, which suggested that entomic protective enzyme activities were related to a resistance and react that the resisting capacities of P. rapae and T. molitor increased, which will be guiding senses on studying inhibitor of protective enzymes to overcome resistance to pests. When infected by EPN 24 hours, obvious symptoms appeared that was soft body and infection with the time going, the entomic body had fragrance and the body was more and more soft. Such symptoms were due to the decomposition of the organization. caused by large number of EPN. When infected by EPN 16-24hs, SOD and POD activities began to decrease but it was 32nd hour of the beginning of the decline in CAT.After the infection by two kinds of EPN, SOD activity reached the maximum at different time in P. rapaes. It was at 16th hour that SOD activity reached the maximum infected by S. feitiae, but it was at 24thhour by H. megidis. Vigors of CAT and POD activities were respectively similar infected by S. feitiae and H. megidis.