Studies On The Effects Of Bt Cotton On Propylaea Japonica

The population dynamics of Propylaea japonica (thunberg) on Bt cotton were preliminarily investigated from June to October, 2003 in Langfang City, Hebei Province of northern China. The results indicated that during growing stage of hosts, the population of thunbergs in Bt cotton field were much more than that in Non-Bt cotton field, which increased continually and up to a peak around on 30rd July, then gradually decreased.The results showed that there were no significant differences in the development duration among the thunbergs reared on Aphid which collected from Bt cotton field and Non-Bt cotton field, respectively. The survival rate of larvae and pupae that reared on Aphid which collected from Bt cotton field were significant lower than that reared on Aphid which collected from Non-Bt cotton field. There were significant differences in the body weight of third, fourth larvae and pupae, but no significant differences to the second larvae that reared on Aphid which collected from Bt cotton field and Non-Bt cotton field, respectively.The activities of detoxification enzymes and major protease isolated from Propylaea japonica were detected in the laboratory. The results indicated that except for several detoxification enzymes and major protease showed no differences on the activity between thunbergs collected from Bt cotton field and Non-Bt cotton field during several stage, there were significant differences on the activities of a -naphthylacetate esterases, acetylcholinesterases (AchE), glutathione-S-transferase, acid phosphatase(ACPH) and alkaline phosphatase(ALP) during the growing stage of cotton and thunberg. And there were significant differences on the activities of the total protease, active alkaline trypsin-like enzyme, weak alkaline trypsin-like enzyme and chymotrypsin-like enzyme between the thunbergs which collected from Bt cotton and Non-Bt cotton field, respectively.The content of Bt (Bacillus thurngiensis Berliner) insecticide protein (BtIP) in thunbergs was studied by ELISA in laboratouy. The results showed that there were obvious spatio-temporal changes of the contents of BtIP along the development process of Bt transgenic cotton. The BtIP could been detected in second and fourth larvae during the cotton squaring stage to flowering stage, and the contents were 4.89ng/g and 13.36ng/g, respectively. But the BtIP could not been detected in other stages of thunbergs. And during the cotton flower boll stage to boll stage, the BtIP also could not been detected in any stages ofthunbergs.