转抗虫基因杨树对土壤微生物影响分析

Effects of transgenic insect-resistance hybrid poplar 741 groves on soil microorganisms

以4年生转双抗虫基因741杨试验林为对象,研究了土壤中Bt毒蛋白的分布,及其在生长季节中土壤微生物种群数量的变化。结果表明:试验林土壤中发现了毒蛋白的存在,在转基因植株根围含量最高,距根系越远,含量逐渐降低。其毒蛋白分布趋势是根组织>根际土壤>根围土壤>地表土,其浓度一般呈10倍的等级降低,在非转基因对照植株根系周围未检测到毒蛋白存在。转基因741杨试验林中,根际、根表土壤细菌、放线菌数量存在季节变化模式,春季开始,数量逐渐增加,6、7月份数量最多,以后又逐渐下降。转基因植株和非转基因植株之间不同时期根际和根表土壤细菌、放线菌和真菌数量存在一定差异,但未达到统计学显著水平。试验证明,转基因741杨在砂质土壤中Bt毒蛋白的分布与微生物种群数量变化无明显关系,具有生态安全性。

In order to evaluate ecologic safety of transgenic insect-resistance hybrid poplar 741,the diversity of soil microflora and Bt toxin protein were systematically studied in the growth season.4-year-old transgenic poplar 741 in the Heneshui district and Baoding district were examined.The toxin protein was found in the soil of 4-year-old test groves,whose peak content appeared in rhizosphere,and the longer the distances off the roots,the lower the contents.The distribution of toxin protein showed a descending trend： root tissue 〉root surface soil〉 rhizosphere soil 〉surface soil.The concentration of toxin protein decreased by degree of 10 times among different parts of soil.No toxin protein was found in rhizosphere of non-transformed clones.In the rhizosphere and roots surface soil of 4-year-old test groves,the amount of bacteria and actinomycetes and fungi varied with the changes of season.In spring,their amount began to increase gradually,reaching the maximum in June and July,and then decreased gradually.Between different transgenic clones and nontransgenic controls,during different seasons there were differences but no significant difference of their amounts appeared in rhizosphere and roots surface soil.The existence of toxin protein in soil showed no significant influence on the amounts of fungi,bacteria and actinomycetes.The result showed that distribution of Bt toxin protein was not related to the amount of microorganism.Transgenic poplar is ecofriendly in the grittiness soil.