Influence Of Transgenic Populus Simonii×P.nigra's Root Secretion On Soil Ecosystem

At present,more and more countries grow transgenetic crop which resist pests or herbicide,so it has already arouse people's attention to the influence of transgenic plants on ecological environment. The soil is not only the transgenetic plants' living environment,but also the obvious object the transgenetic plants impact on. Therefore,the paper primarily researched that transgenic Populus simonii×P.nigra' root secretion influenced on microbial structure and quantity,soil enzyme activity,nutrient and the horizontal transfer probability of the exogenous gene in soil. It provided the useful information for evaluating the risk of ecological environment from releasing transgenic plants, and also provided reference for advanced research about the influence the transgenetic plants impact on the environment.The research showed that after planting for seven months the transgenic Populus simonii×P.nigra affect the soil enzyme activity differently with them after planting for one month. The activity of Phosphatase and Polyphenol oxidasein declined while the Urease advanced,among which the Phosphatase declined most. The experiment showed that the transgenic Populus simonii×P.nigra affected to the soil enzyme activity to some extent, but it's not markedly different with control in statistical level,so it may showed that the soil enzyme activity isn't influenced by the transgenic Populus simonii×P.nigra for a large extent.The research showed it was tiny that the main soil nutrient was changed with the root secretion of transgenic Populus simonii×P.nigra in short term, most of them were not markedly different with control(P>0.05).Some of them were markedly different with control after one month's planting,but after planting seven months when the bloom period came,the total phosphorous,slowly available potassium,fast available potassium,inorganic carbon,total carbon and water soluble salt in the soil which interred transgenic root secretion, were not markedly different with control(P>0.05)except the hydrolysable nitrogen. So, we deemed that it was tiny that the main soil nutrient was changed with the root secretion of transgenic Populus simonii×P.nigra in short term. Nevertheless, whether the root secretion of transgenic Populus simonii×P.nigra had the influence to the soil nutrient or not, and yet it needed to be further verified.In the paper we researched five soil microbes beside root which are 1-5 cm far from the main root and 4-7 cm far from the topsoil- Bacteria,Actinomyces,Fungi,Diazotroph and Cellulose-decomposing bacteria, and figured out their number to find out the transgenic Populus simonii×P.nigra's influence on the microbes around the root compared with Ck and Blank . The research showed that the transgenic Populus simonii×P.nigra can change the number of the microbes. At beginning,they can change it quickly,while when they developed for a while the number didn't change evidently except for fabrin decompose bacteria.Besides,after planting for a while,the microbes' number of the transgenic Populus simonii×P.nigra became a little more than the Ck,which showed that the BT aim gene can boost the number of soil microbes and made the soil fertile. Otherwise, with a view to the scale of the soil microbe totality in different decomposing times, the number of bacteria was higher than other microbes in this study. So, bacteria is the most predominant in soil microbes at five different times.This paper detected that the PCR result of NPT II gene from soil bacteria which live around the root, was higher than control after seven months'planting. In detecting the PCR positive result of NPT II gene, we justly detected few positive result, whose PCR positive result was merely 6%-10% after planting for one month to 34%-46.67% after seven months. The two periods presented distinct level (P<0.05). In detecting the PCR positive result of Bt-the spider insecticidal peptide gene, we justly detected few positive result, whose PCR positive result was none after planting for one month to 2%-5% after seven months. And the reason was related to the horizontal transfer of aim gene; moreover, the result of sourthern blotting further approved the conclusion.