转Bt基因棉粉碎叶还土对土壤微生物活性的影响

Effect of Ground Leaves from Transgenic Bt Cotton on Soil Microbial Activity

为评价转Bt基因棉残体还田的生态效应,采用室内模拟试验方法,研究了转Bt基因棉粉碎叶还土后对土壤微生物活性的影响。结果表明,转Bt基因棉粉碎叶还土后在腐解中期可显著增加土壤细菌、真菌数量,对放线菌无明显影响。转Bt基因棉粉碎叶物质组成或Bt蛋白外的降解产物等方面的不同可能是对土壤微生物影响更为主要的原因。转Bt基因棉粉碎叶还土腐解中期显著提高土壤微生物生物量碳,但土壤基础呼吸和代谢商显著降低,表明转Bt基因棉粉碎叶还土土壤微生物对能源碳的利用效率提高了。

Using the simulation lab experiment, the effects of transgenic Bt cotton tissue on soil ecology system, espe cially on soil microbial activity were investigated. The results showed that when added the grounded residue of Bt transgenic cotton into the soil, the population of soil bacteria and fungi at cultivated middle stages were increased sig- nificantly compared with conventional cotton, but no effect on the population of soil actinomycetes was observed. It could be the difference in composition of transgenic Bt cotton or degradation product besides Bt protein resulting the difference. Transgenic Bt cotton treatments also significantly increased soil microbial biomass carbon and decreased basal respiration and microbial metabolic quotients at cultivated middle stage, which indicated that soil microbial com-munity improved the potential utilization of carbon substrate.