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转Bt+CpTI基因棉因其具有强有效的杀虫性能,近年来种植面积不断扩大,其种植对土壤生态系统的影响是环境风险评价的重要组成部分。本研究以转基因双抗虫棉sGK321和亲本同源常规棉石远321为研究对象,通过比较分析了不同生育期(苗期、蕾期、花铃期、吐絮期)转双价基因棉与其非转基因棉亲本在大田条件下种植13年后,根围土壤酶活性(脲酶、碱性磷酸酶、过氧化氢酶)变化和土壤可培养微生物(细菌、真菌、放线菌)数量的变化。结果表明,转双价棉与常规棉根际土壤脲酶、过氧化氢酶和碱性磷酸酶活性以及土壤可培养细菌、真菌、放线菌数量随生育进程的推进变化趋势一致。土壤细菌和放线菌数量在同一时期均无显著差异;土壤脲酶、过氧化氢酶、碱性磷酸酶和土壤真菌数量在一些时期差异明显,转双价棉脲酶苗期、碱性磷酸酶苗期和蕾期,土壤可培养真菌数量花铃期低于常规棉,土壤过氧化氢酶苗期、碱性磷酸酶花铃期高于同源常规棉。聚类分析表明,土壤酶活性和土壤微生物种群数量变化主要受生育期的影响,而转双价Bt+CpTI种植对土壤酶活性和微生物影响是有限的。
Due to its strong insecticidal properties, transgenic Bt + CpTI cotton has been expanding its planting area in recent years and its impact on soil ecosystem is an important part of environmental risk assessment. In this study, transgenic double insect-resistant cotton sGK321 and its parental conventional cotton stretcher 321 were selected as the research objects. By comparing and analyzing the transgenic cottons with different growth stages (seedling stage, bud stage, boll stage and boll stage) Changes of soil enzyme activities (urease, alkaline phosphatase and catalase) and quantities of soil-culturable microorganisms (bacteria, fungi, actinomycetes) of transgenic cotton parents after 13 years of planting in the field. The results showed that the activities of soil urease, catalase and alkaline phosphatase in soil rhizosphere and the amount of bacteria, fungi and actinomycetes cultivable in the rhizosphere soil of transgenic cotton and conventional cotton were the same as the growth progress. There was no significant difference in the number of soil bacteria and actinomycetes in the same period. The number of soil urease, catalase, alkaline phosphatase and soil fungi varied significantly at some time. The number of fungi capable of culturing in soil was lower than that of the conventional cotton during the boll stage and the cotyledon stage of soil CAT and the boll stage of alkaline phosphatase were higher than that of the conventional cotton. Cluster analysis showed that the changes of soil enzyme activity and soil microbial population were mainly affected by the growth period. However, the effects of bivalent Bt + CpTI planting on soil enzyme activities and microorganisms were limited.