| The relationship between host preference of Liriomyza huidobrensis Blanchard, plant phylogenesis relationship and physical characteristics of leaf was studied; Both the adaptation of the leafminer to the non-host plant—wheat and the activities changes of endogenous enzymes are evaluated. The major results obtained were as follows: 　Forty-three were selected for feeding and twenty for oviposition among fifty-seven species of test plants, the percentages of feeding and oviposition were 75.4% and 35.1%, respectively. Its acceptability index for feeding and oviposition was positive to the index of plant relationship. 　2nd-instar larvae were manually transferred from the preferred plants broad bean (Vicia faba L.) to fifty-five species test plants. Larva could complete its development in thirty-nine plants, the percentage was 70.9%, which was far higher than the percentage of adult oviposition (35.1%). It shows that larvae had more potential on host range. 　The ratio of feeding, oviposition activities and pre-oviposition on the wheat were 1/23,1/16,4.4-fold compared with on the broad bean, respectively. There was significant difference. It indicated that the fitness of wheat to L.huidobrensis was poor. The ratio egg deposition: feeding in each generation on the wheat, which was significantly higher than that on broad bean suggests that the wheat was more unsuitable for feeding. 　Feeding and oviposition quantity of L.huidobrensis from wheat back to broad bean were much lower than those fed on broad bean all the time and there were significant difference between F1, F2 and initial generation. It shows that L.huidobrensis had adapted to the wheat to some extent, and was capable of adapting to a new host rapidly. 　he correlation between feeding punctures and density of palisade tissue, sponge tissue were negative significant (p＜0.05), and the latter was negative significant with selective grade too. Feeding and oviposition activities were more affected by density of palisade tissue than by sponge tissue. The more higher density of palisade tissue, the less preference of the feeding and oviposition of female adult. The correlation between survival rate of larva and density and thickness of palisade tissue was negative significant. Higher density of palisade tissue acted as the resistance character affecting the mining and development of larvae, but it was positive significant between survival rate of larvae and thickness of sponge tissue (p＜0.01); The more of thickness of sponge tissue, the more of feeding activity of larvae, which shows larvae preferred sponge tissue. 　 With the adaptation of L. huidobrensis to wheat, the activities of carboxylesterase(CarE) and acethylcholines(AchE) increased on some degree. The CarE was the main detoxification enzyme to metabolize toxin of wheat and decrease the harm to L. huidobrensis. 　Glutamate(Glu) was necessary for L. huidobrensis which could be formed by transamination of alanine transaminase(ALT) and aspartic transaminase(AST), so that could increase the suitability of wheat to L. huidobrensis. On wheat the activities of ALT of L. huidobrensis in F1,F6 generation were much higher than that of other generations. The activity of AST of L. huidobrensis in F1 generation was the highest on wheat, but was far lower than that on broad bean. The correlation between the weight of pupae and the activity of AST was positive significant.　　Peroxidase(POD), superoxide dismutase(SOD) belong to the endogenous enzymes of protective system, The levels of POD activity in F1 and F6 generations, SOD activity in F6 were enhanced obviously, which showed that the adaptation of L.huidobrensis to wheat was increased gradually. The level of activities of three type endogenous enzymes was mostly enhanced on F1 generations, so F1 generations was the key period for L.huidobrensis to adapt to wheat.
|
PDF Full Text Request