The Study On Soil Biota Community Of The Divalent Transgenic Insect-resistant Hybrid Poplar741 Forest

The influences of transgenic crops on soil ecosystem is another important problem after many problems such as gene transfer from transgenic plants to related wild species ,effects on non-target organisms and resistance in target pests, it is one of important matters in ecological risk assessment of transgenic crops at present time. The transgenic insect-resistant hybrid poplar741 used in this test were high insect-resistance hybrid poplar741(Pbl 1, Pb29, Pb3) and medium insect-resistance hybrid poplar741(Pb!7 , Pbl2). We have made an serial investigation on the community of soil arthropod and the number of soil microbes and soil nematodes in rhizospheric mini-field soil of Pb29, Pbl7 and the normal hybrid poplar741. At the same time, we have made an serial investigation on the leaf litter decompose of Pb3, Pbl2 and its impact on arthropod, microbes and nematodes in the around circumstance. Moreover, the toxic protein in leaf of high insect-resistance hybrid poplar741 and medium insect-resistance hybrid poplar741 was measured by the ELISA method. And the result was proved by biological test. The results of this study are as follows.(l)The species of soil arthropod in rhizospheric mini-field of the divalent transgenic insect-resistant hybrid poplar741 do not have evident increase. But the individual quantity has notable increase for the individual quantity of superiority species in community has notable increase. The feature indices of diversity and even degree in the community of soil arthropod in rhizospheric mini-field of the transgenic insect-resistant hybrid poplar741 had decreased evidentely, but the index of superiority had increased, the community structure are less reasonable; The number of soil microbes in rhizospheric mini-field of the high insect-resistance hybrid poplar741 has increased evidently, but the number of soil microbes in rhizospheric mini-field of the medium insect-resistance hybrid poplar741 has decreased evidently; The number of soil nematodes in rhizospheric mini-field of transgenic insect-resistant hybrid poplar741 has not evident changing-regular.(2)The number and the dynamic of quantity of arthropod in leaf litter have not evident change. And the individual quantity of arthropod in soil around leaf litter has notable increased. But the community structure are less reasonable, the stability of community has decreased. The number of microbes and soil nematodes has decreased evidently. The decomposition speed of leaf litter of transgenic insect-resistant hybrid poplar741 is quickerthan the normal poplar741 at the initial stage of take a sample, their decomposition speeds are consistent with each other gradually along with time. It is obvious that the soil arthropod has taken the more important effect in the decomposition of withering and falling.(3)The toxic protein in leaf of high insect-resistance hybrid poplar741 is more than medium insect-resistance hybrid poplar741, it is becoming more and more along with leaf-opening time, which is accord with the result of biological test. The leaf of normal poplar741 have no toxic protein. The toxic protein content in leaf is the major factor in resulting to the death of insect.