Studies On Effect Of Transgenic Chi+Glu Cotton On Dynamic Change Of Enzyme Activities And Functional Diversity Of Soil Microbial Community

Transgenic cotton is one of the most widely cultivated transgenic plants in the world, Whose effects on the ecosystem have always been concerned these years. In this study, transgenic Chi+Glu cotton, Zhongmiansuo24, which were supplied by the Cotton Research Institute of CAAS, were selected as the materials for studying the ecological security of transgenic Chi+Glu in the field.In 2009, the activities of Invertase, Urease, Alkaline phosphatase, Catalase, Dehydrogenase in soil in which grown transgenic Chi+Glu,Bt cotton and un-transgenic conventional cotton were tested in different cotton growth period in the field. The result showed that transgenic Chi+Glu cotton in different growth period played a promoting effect on activities of invertase, catalase and dehydrogenase in soil, while, to some degree, it inhabitted urease and alkaline phosphatase in soil.In 2010, the functional diversity of soil microorganism community of transgenic Chi+Glu cotton, transgenic Bt cotton and un-transgenic cotton in different growing stages were analyzed by Biolog Metabolic Fingerprinting method. Although there was no significant difference in the number of soil microorganism community between two transgenic cottons, the number of soil bacteria and actinomycetes of transgenic cotton were significantly higher than that of un-transgenic cotton in stages of flowering and boll-forming stages, while the number of soil fungi was significantly lower than un-transgenic cotton. Compared with un-transgenic cotton, transgenic cotton had less effects on the carbon source utilization ability, Shannon functional diversity index, Simpson index and McIntosh index of soil microbes at sowing, seeding, squaring and boll-opening stages, but increased the carbon source utilization ability, Shannon functional diversity index and McIntosh index at flowering and boll-forming stage significantly, while its Simpson index was significantly lower in the flowering and squaring stages. The principal component analysis showed that the 31 carbon sources utilized by the transgenic and un-transgenic cottons had significant difference in the flowering stage. In the squaring stages, the transgenic cotton had a higher utilization of carboxylic acids, amino acids and amines than that in un-transgenic cotton. It also indicated that in the boll-opening stage, the transgenic cotton had a higher utilization of carbohydrates and carboxylic than un-transgenic cotton and the two transgenic cottons had a low utilization of carbon sources.Based on the above results, the planting of transgenic cotton had influences on each indicator of soil to different extent in the whole process of cotton life, and the range of influence showed to be different as well. The results also showed that in terms of the soil enzymatic activity and microbe population diversity, the transgenic cotton indicated some differences compared to un-transgenic primarily in the stage of flowering and squaring, although the Chi+Glu cotton and Bt cotton had no significant differences. Therefore, transgenic Chi+Glu cotton did not effect the safety of cotton soil ecosystem.This study supplied scientific references for assessing the potential risks of planting transgenic Chi+Glu cotton to the soil microbial community. Besides, the results also offer a theoretical guidance for the possibility of planting Chi+Glu cotton in the field.