Studies On The Community Structure And Abundance Dynamics Of Soil Animal In Transgenic BT Rice Paddyfields

Transgenic Bt rice had provided an efficient technology for reducing rice losses resulted by insect pest. Howerever the Bt protein released to soil ecological system by rice may produce environmental risks.Soil ecosystem is an important place in material cycle and energy conversion,and long-term cultivation of transgenic Bt crops could make the outside source Bt toxin protein accumulated in soil, so that it may influence on soil organisms to varying degrees.In recent years, with the speeding up of transgenic Bt crop commercialization, the ecological risk assessment of transgenic Bt rice on soil ecological system cause the attention of many scholars. Collembola, mites, nematodes are the commom three categories soil indicator animals, their large quantities and multiple nutrition groups make they occupy key positions in soil food web. Analysis the community change can reflect the comprehensive condition of the structure of soil food web and function.So they have unique advantages in evaluating soil ecological security.This study selected fusion Cryl Ab/Cryl Ac Bt rice genotype HH1and its parent MH63rice to study the community composition and number of dynamic of the above three soil animals in the rice fields and in the climate change of CO2and temperature, especting to clear and definite the security of the soil ecological. The main results are as follows:1. The influence of transgenic Bt rice on soil collembolanFrom the conclusion of field study, it was shown that there weren’t negative effects on collembolan when transgenic Bt rice was planted. On the contrary, it can increased the totale ollembolan number and increased community diversity and community evenness of the soil collembolan. While the results were not consistent between the two years. Beside, the planting of transgenic Bt rice resuited the loss of some rare taxa.From the conclusion of climate change study, it was found that high temperature has a tendency to reduce the number of the soil collembolan, especially in elevated CO2. The same that the results are not consistent between the two years. The number of soil collembolan was influenced by time obviously.2. The influence of transgenic Bt rice on soil mitesFrom the conclusion of field study, it was indicated that there weren’t negative influence on the number, community diversity, species richness and community evenness of mites when transgenic Bt rice was planted. For the community composition of mites, there also does not have significant effect,besides transgenic Bt rice made the percentage content of Xylobates significantly decreased by45.18%in2009.Other mites are not influenced by transgenic Bt significantly.From the conclusion of the climate change study, it was shown that CO2, temperature and transgenic didn’t influence the number of mites obviously, and there are no interactions. Just in2010, transgenic rice significantly reduced the number of soil mites in the high CO2and low temperature conditions.3. The influence of transgenic Bt rice to soil nematodeDifferent types of nematodes have different corresponding to transgenic Bt rice. Transgenic Bt rice planting significantly decreased the percentage content of Acrobeloides in2009, while significantlyincreas the percentage content of Cephalobus in2010. The planting of transgenic Bt rice caused the loss of some rare taxa. In addition, according to the results of2010,transgenic Bt rice significantly reduced the number of soil nematodes, while there was not significant impacts on the other soil nematodes.