Studies On The Developmental Effects, Phisiological And Biochemical Mechanisms Of Transgenic Cry1Ac And Cry1A+CpTI Cottons On Beet Armyworm Spodotera Exigua (Hübner)

A series of experiments were carried out on the effect of transgenic CrylAc cotton (NuCOTN33B), transgenic CrylA cotton (GK-12) and transgenic CrylA+CpTI cotton (SGK-321) on the development, nutrational and respiratory metabolism, and the mechanism of pathology and biochemistry. The results could be summarized as follows.1.After the new incubated larvae fed on transgenic cottons in different periods, the mortality, larval weight, pupation, pupal weight and eclosion declined, and the larval and pupal duration were prolonged. RGR, ECI and ECD of larvae decreased, and yet RCQ, HAD and RMR of larvae increased after feeding on the transgenic cottons. NuCOTN 33B was the most toxic to beet armyworm, indicating the gene CrylAc was the most effective. SGK-321 and GK-12 had the same effect on the young larvae, but SGK-12 was more effective on old ones.2.Larva respiratory metabolism would change after larvae fed on transgenic cottons. With larvae growing, larval respiration rate decreased, and oxygen uptake increased. Compared with the larvae feeding on non-transgenic cottons, the respiratory rate and oxygen uptake of those feeding on transgenic cottons fluctuated more frequently. To the larvae feeding on non-transgenic cottons, their weight were positivelay correlated with oxygen uptake, but the rule was not adaptive to those feeding on the transgenic cottons.3.After the new incubated larvae fed on transgenic cottons, the activities of AChE and AKP of the third instar larvae decreased with GST increasing. The activity of CarE of the larvae feeding on NuCOTN 33B declined, and the activity of ACP did not change significantly. The activity of CarE of the larvae feeding on SGK-321 increased, and the activity of ACP declined. The results of esterase of larvae feeding on different cottons were analyzed with PAGE. The analysis showed that enzyme band E8 became clearer after larvae fed on transgenic cottons, and bands E2-5 were different for the cottons. Enzyme57band E6 and E7 were common to all the larvae. The results of defedant enzymes showed that the activity of SOD did not change significantly, and the activities of POD and PPO increased after larvae fed on transgenic cottons. If the larvae fed on artificial forage to the third instar, and then fed on cottons, the activities of the total protease, active alkaline trypsin-like enzyme and weak alkaline trypsin-like enzyme increased and chmotrypsin-like enzyme activity declined. If the new incubated larvae fed on cottons, the activities of protease detected all declined.4. Under electron-microscopy, the midgut tissues of the 9d, 14d and 18d larvae feeding on transgenic cottons were physiologically and pathologically changed. The main changes were in the midgut microvilli, endoplasmic recticulum, mitochodria and the cell nucleolus. After larvae fed on the leaves of transgenic cottons, the midgut microvilli swelled and then fell off. The intersoace of the endoplasmic recticulum expanded and then hollows formed. The mitochondria swelled, and then cristae mitochondriales were absent. The cell nucleolus was distoted, and the chromatin got together. When larvae were injured badly, the membrane of the cell and nucleolus would break off.