Study On The Environmental Safety In Aquatic Ecosystem Of Transgenic Bt Rice

Since the emergence of the first transgenic Bt plant in1986, an incrensing attention has been paid on the potential ecological risk brought about by the transgenic Bt plants. Laboratory and field studies using two transgenic Bt rice, Minghui 63 and Shanyou 63 containing a synthetic gene cry1Ab/cry1Ac,were carried out to investigate the degradation dynamics of insecticidal proteins in water and soil and the impact on aquatic animals.The results are as follows:1 the impacts of insecticidal protein in transgenic Bt rice on the aquatic communitiesFrom the dynamic changes of the number of individuals in different aquatic communities of rice fields, the main parameters, the distance factor and the community in terms of similarity coefficient, Bt-transgenic rice fields and conventional fields have no significant difference, but Bt toxin may inactivate or degradate due to many factors, and the fields only plant transgenic Bt rice in two years, also perhaps due to less Bt rice plants Litter left in the water or shorter investigation periods of time, so further studies need to be carried out to confirm whether Bt rice has impact on aquatic animals or not.2 the residue of insecticidal protein in the water of transgenic Bt riceThe results showed that:during the period of the late tillering and milky stage of rice, insecticidal protein were left in the water of transgenic Bt rice,.In the stage of late tillering:,the average content of insecticidal protein in Bt Minghui 63 and Bt Shanyou 63 rice fields water were respectively 0.82ng/ml and 089ng/ml; jointing stage, respectively 0.77ng/ml and 0.63ng/ml; booting stage both 0.59ng/ml; flowering stage, respectively 0.61ng/ml and 0.67ng/ml; and milky stage are respectively 0.56ng/ml and 0.62ng/ml. In the lower reaches of non-Bt rice fields and water of ponds, the content of Bt insecticidal proteins are not detected. Studies have shown that the release of Bt-transgenic rice Bt insecticidal protein may be residual in the water, but the low levels water will not have a significant impact.on field water and downstream. 3 the residue of insecticidal protein in the soil of transgenic Bt riceAfter harvest, soil the toxic protein were detected in Bt Minghui 63 and Bt Shanyou 63 paddy, the content of which were respectively 0.0235±0.0166ng/g and 0.057±0.0037ng/g,That toxic protein can be residue in the soil, but the residual volume is very low. In the non-Bt rice fields, as well as downstream of the soil,toxic protein were not detected,.The result shows that transgenic Bt rice fields have not a significant impact on the downstream field and downstream soil.The results of further study on the content of Bt toxic protein in the vertical distribution of soil showed that the content of toxic protein inlOcm deep of soil was 0.05475±0.0083ng/g, in 20cm deep, the content of toxic protein was 0.0435±0.0019 ng/g, in 40cm deep, the content of toxic protein was 0.03575±0.0075ng/g,and in 60cm deep, the content of toxic protein was 0.02475±0.0089ng/g. Studies have shown that the content of toxic protein in the soil will show a falling trend with depth,.In 80cm deep of soil, toxic proteins were not detected.