苏云·稻纵颗与化学农药施用下稻田土壤微生物数量和代谢功能多样性的差异

Differences in soil microbial abundance and metabolic functional diversity under application of CnmeGV·Bt and chemical pesticides in paddy fields

  • 摘要: 为了明确长期使用微生物杀虫剂和化学农药对水稻田土壤微生物种群数量和代谢功能多样性的影响, 本文采用分离培养技术和Biolog微平板法相结合对长期施用微生物农药苏云·稻纵颗(CnmeGV·Bt)和化学杀虫剂的稻田土壤微生物数量、代谢功能活性及碳源利用类型多样性等进行研究。结果表明: 与常规化学杀虫剂相比较, 施用CnmeGV·Bt后土壤中细菌、真菌、放线菌数量均显著增加, 分别为化学杀虫剂处理的1.86倍、1.75倍和1.34倍。进一步筛选发现真菌中木霉菌数量高于化学杀虫剂处理, 差异显著。细菌中芽孢杆菌、溶磷功能菌、解钾功能菌数量与化学杀虫剂处理无显著差异。不同处理后土壤微生物群落平均颜色变化率(AWCD值)随时间变化趋势基本一致, 开始的48 h AWCD变化很小, 48~144 h快速升高。CnmeGV·Bt处理后AWCD值在48~192 h均显著高于化学杀虫剂处理。CnmeGV·Bt处理后土壤微生物群落Shannon多样性指数之间无显著变化, Simpson指数和Invsimpson指数显著提高。CnmeGV·Bt处理后土壤微生物对多种类型碳源的利用发生变化。对7种糖类、2种氨基酸类、6种己糖酸类、7种羧酸、酯和脂肪酸类的利用强度显著高于化学杀虫剂处理。对4种糖类、3种羧酸、酯和脂肪酸类的利用强度显著低于化学杀虫剂处理。主成分分析表明, 与CnmeGV·Bt处理相关的碳源主要是葡糖醛酰胺、黏液酸、果胶、L-鼠李糖、ß-甲酰-D-葡糖苷等, 与化学杀虫剂处理相关的碳源主要是龙胆二糖、L-岩藻糖、D-苹果酸等。研究结果说明稻田应用微生物杀虫剂替代化学杀虫剂能够促进土壤微生物数量及其代谢功能, 对于Bt类生物农药应用的环境行为及生态效应评价具有重要意义。

     

    Abstract: To elucidate the long-term impact of microbial insecticides on the population abundance and metabolic functional diversity of soil microorganisms in rice paddies, we employed a combination of isolation culture techniques and the Biolog microplate method to conduct comparative studies on the diversity of soil microorganisms with long-term application of microbial insecticide CnmeGV·Bt and chemical insecticides, and to analyze microbial population dynamics, metabolic functional activity, and carbon source utilization diversity. The results indicated that, compared to aplicaion of conventional chemical insecticides, application of CnmeGV·Bt significantly increased the populations of bacteria, fungi, and actinomycetes by 1.86, 1.75, and 1.34 times, respectively. Further analysis revealed that the abundance of Trichoderma spp. of fungi was significantly higher under CnmeGV·Bt treatment than under chemical insecticidal treatment, whereas the populations of Bacillus spp., phosphate and potassium solubilizing bacteria, showed no significant differences. The average well color development (AWCD) values of soil microbial communities exhibited similar trends over time across treatments, with minimal changes in the first 48 h, followed by a rapid increase between 48 and 144 h. Notably, AWCD values were significantly higher in the CnmeGV·Bt-treated soil from 48 to 192 h than those in the chemical insecticidal treatment. The Shannon diversity index of soil microbial communities showed no significant differences between treatments, whereas the Simpson and inverse Simpson indices were significantly elevated under CnmeGV·Bt treatment. Compared with chemical insecticidal application, the microbial utilization of various carbon sources shifted following CnmeGV·Bt application, with significantly higher utilization intensities observed for seven carbohydrates, two amino acids, six hexose acids, seven carboxylic acids, esters, and fatty acids. Conversely, four carbohydrates, three carboxylic acids, esters, and fatty acids were less intensively utilized. Principal component analysis identified specific carbon sources associated with CnmeGV·Bt treatment, including glucuronamide, mucic acid, pectin, L-rhamnose, and β-methyl-D-glucoside, whereas chemical insecticidal treatment was linked to gentiobiose, L-fucose, and D-malic acid. These findings demonstrate that replacing chemical insecticides with microbial insecticides in rice paddies can enhance the soil microbial abundance and metabolic function. The results provide critical insights into the environmental behavior and ecological effects of Bt-based biopesticides.

     

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