| With the rapid development of biological science and technology, transgenic technology be exploited more and more widely in the production and application of life, while the biosafety issues be much noticed by the public.Therefore, the research about potential biosafety of arthropod community which caused by transgenic poplars’ large-scale planting is becoming increasingly urgent. In order to provide a scientific basis for the ecological safety assessment and rational utilization and extention of transgenic hybrid poplar 741, effect and its rules of the transgenic poplar on arthropod community structure,characteristics and dynamics were studied by the investigation to the community of transgenic Bt Cry3 A and Bt Cry1 Ac gene poplar. The main results are as follows:1. Effects of transgenic Bt Cry3 A and Bt Cry1 Ac gene poplar 741 on arthropod community structureThe two kinds of transgenic poplar 741, especially the transgenic Bt Cry1 Ac gene poplar 741 had obvious inhibition on insect, which not only had inhibition on Lepidoptera and Coleopteran insects; but also can effectively reduce the quantity of non-target Hemiptera sucking insects(Hemiptera and Homoptera suborder), and had a beneficial effect on natural enemies. And the arthropod community composition of two kinds of transgenic hybrid poplar 741 were complicated, and the sequence as that Bt Cry3 A poplar > Bt Cry1 Ac poplar > CK. Statistics show that the transgenic Bt Cry3 Ac gene poplar 741 had not obvious inhibition on Coleopteran insect. The individuals of phytophagous sub-community were sharply fewer than that of control. The results showed transgenic hybrid poplar 741 had a better resistance on insects.And the sequence of insect-resistance as that transgenic Bt Cry1 Ac gene poplar stand > transgenic Bt Cry3 A gene poplar stand. The quantity of predacity natural enemy insects of the two gene transgenic poplar stands were some more than that of control poplar stand, but the neutral insects had no obvious change.2. Effects of transgenic Bt Cry3 A and Bt Cry1 Ac gene poplar 741 on nutritional structure of arthropod communityCompared to the control, the basal species of transgenic Bt Cry1 Ac gene poplar community was almost no difference, and the richness of basal species of transgenic Bt Cry3 A gene poplar community had increased. The number of Lepidoptera and Hemisphere insects was significantly reduced and the species richness varied in the sequence as that CK > Bt Cry3 A poplar > Bt Cry1 Ac poplar. The results showed that target and non-target insects were restrained by two kinds of transgenic gene poplars.The richness of intermediate species(predator natural enemy) had increased, but the top species were not difference. The composition and quantity of the functional groups in transgenic Bt Cry1 Ac gene poplar stand were no difference than that in the control, but less than that in the transgenic Bt Cry3 A gene poplar stand.3. Effects of transgenic Bt Cry3 A and Bt Cry1 Ac gene poplar 741 on characteristic index of arthropod communityThe diversity index and evenness index of the two kinds of transgenic poplars communities were slightly higher than that of control, but the dominant index lower than that of control, and the trends of dynamic changes were showed consistent. Combined with the relative stability index(S/N, S1/S2, N1/N2) of transgenic poplar arthropod community and its dynamic variation, it indicated that the food chain and food webs of arthropod community in the two kinds of transgenic poplars were more complicated, and the constraining effect between different nutritional classes was more obvious.The characteristics index of the two transgenic poplars were significantly different. It proves that the relationship between the structure and composition of the two kinds of transgenic poplars were more complicated than that of the control, and the sequence of each index was as that Bt Cry3 A poplar > Bt Cry1 Ac poplar > CK.The results indicated that the two kinds of transgenic poplars stand can raise the diversity of arthropod community to a certain extent.4. Effects of transgenic Bt Cry3 A and Bt Cry1 Ac gene poplar 741 on temporal dynamics of arthropod communityShowing an obvious regularity, the change of arthropod community composition, quantity and diversity in transgenic poplars stand was relatively stable. Throughout the investigation period, the amount of occurrence and change width of insect in the control were higher than that in the two transgenic poplar stand. The insect population reached a peak in August in the two transgenic poplars stand, and the number of insects had a downward trend in the transgenic Bt Cry1 Ac gene poplar stand, but it was on rise in the transgenic Bt Cry3 A gene poplar stand. The species of insect in transgenic Bt Cry3 A gene poplar stand had been higher than that in the others, and the species of insect was highest in August, then had a slight decline in September, which indicated that transgenic poplar had inhibitory effect to the insect population. The diversity index, evenness index and dominant index within six months changed a wavy undulation over time. The variation of the first two indexs was increase, decrease, and then increase, however the dominant index was on the opposite, which reflected that the community was most complicated in June and the species composition, interspecific relationship and foodweb of arthropods community in transgenic Bt Cry3 A gene poplar stand was more complicated than others.5. The principal component analysis and cluster analysis of transgenic BtCry3 A and Bt Cry1 Ac gene poplar communitiesCluster analysis showed that three kinds of sample plots could be divided into two parts. The transgenic Bt Cry1 Ac gene poplar community was most similar with control, followed with transgenic Bt Cry3 A gene poplar community. And the restrictive function of interspecies relation in the two transgenic poplar communities was better than that in the control... |
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