Influence Of Transgenic Populus Simonii×P.nigra Leaves On Soil Ecosystem

Along with the transgenic technique more and more popular in the world,the influence of transgenic plants on ecological environment is increasingly focused on.Since soil ecosystem is an essential part of total ecosystem,the paper primarily researched that transgenic Populus simonii×P.nigra influenced on microbial structure,enzyme activity,nutrient and the horizontal transfer probability of the exogenous gene in soil.It provided the useful informations for evaluating the risk of ecological environment from releasing transgenic plants and reference for advanced research.The study utilized the soil embedding method of leaf to extend aim gene(Bt-the spider insecticidal peptide gene) and signed gene(NPTⅡgene)in transgenic Populus simonii×P.nigra, and detected their remainder in the soil.The result showed that the aim gene and the signed gene of the transgenic Populus simonii×P.nigra wither in the soil were no more than sixty and ninety days,respectively and both were not detected after 120 days.The paper researched five kinds of soil microbes around leave——Bacteria,Actinomyces,Fungi,Diazotroph and Cellulose-decomposing bacteria,and figured out their number.In the initial stage of leave decomposing,the study found that the wither of the transgenic Populus simonii×P.nigra had influenced on soil Fungi and Cellulose-decomposing bacteria,the differentia of whose the number presented remarkable level with the control(P＜0.05). 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 six different times.This paper detected that the PCR result of NPTⅡgene from soil bacteria which interred transgenic leafage,was higher than control after decomposing.Both differentia 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 merely 1.92%——3.08%.And the reason was related to the horizontal transfer of aim gene;moreover, the result of sourthern blotting further approved the conclusion.The research showed that besides Phosphatase,Urease and Polyphenol oxidasein the soil which interred transgenic leafage,it was markedly different with control.And it maybe imply that to some extent,the soil enzyme activity is mainly influenced by the transgenic Populus simonii×P.nigra in decomposing.However,in the aspect of the soil nutrient,the result showed that when the leaves were interred after a half year,Soil pH value,total nitrogen,hydrolisis nitrogen,soil organic,DOC and DON matter in the soil which interred transgenic leafage, were not markedly different with control,and it justly brought negative effect in Soil available phosphorous.So,we deemed that it was tiny that the soil main nutrient was changed with the decomposition of transgenic Populus simonii×P.nigra leaf in short term.Nevertheless,whether the decomposition of transgenic Populus simonii×P.nigra leaf had the influence on the soil nutrient or not,and yet it needed to be further verified.