代谢指纹评估苯噻草胺对水稻土微生物群落的短期影响

MONITORING OF SHORT-TERM IMPACT OF MEFENACET TREATMENT ON PADDY SOIL MICROBIAL COMMUNITIES WITH METABOLIC FINGERPRINTING

本文探讨了酰胺类除草剂苯噻草胺对水稻土微生物群落功能多样性的短期影响。本研究采用微生物群落基质利用潜力测定(Biolog法)评估生物群落。结果表明,苯噻草胺污染引起了水稻田微生物群落功能多样性的下降,降低了微生物对单一碳源底物的利用能力,但这种影响是短暂的,在试验最终没有导致土壤微生物群落功能多样性下降。多食鞘氨醇杆菌Y1(Sphingobacterium multivorum)的添加有利于提高水稻土微生物群落的功能多样性。3个处理土壤的群落代谢剖面值与培养时间之间呈非线性关系,其变化过程符合微生物种群生长动态模型(S形)。模型模拟分析表明,动力学参数a和x0能更灵敏地表征苯噻草胺和Y1菌株处理对水稻土微生物群落功能多样性的影响。在本实验研究中,多样性指标指数Shannon(H)能灵敏而有效地指示污染环境的微生物学变化,但群落丰富度指标颜色变化孔数(S)提供的信息较片面。

Short-term effect of mefenacet, an acetanilide herbicide, on soil microbial communities in paddy soil was studied. The Biolog method （a kind of colour development assay） was used to determine substrate utilization potential of microbial communities for assessment of biological communities. The results show that functional diversity of the microbial communities decreased, and capability of the microbes of utilizing substrate of simple carbon sources reduced in mefenacet-polluted soils compared with those in non-polluted soil. However, this effect was transient, and functional diversity of the microbial communities in mefenacet-polluted soils came back at the end of the experiment. Supplementation of strain Y1 had a positive effect on metabolic potential of the soil microbial communities. A kinetic method was presented for characterizing the physiological state of microorganisms capable of carrying out specific metabolic function in paddy soils. Test well dye reduction was non-linear in microplates inoculated with duration of the incubation, and the color development curve was generally sigmoidal in shape. Test well 0D values over time suggested a kinetic model based on the density-dependent logistic growth equation. The kinetic parameters generated by the model can be used as surrogates for single-time-point data in constructing carbon source utilization patterns. And a and Xo were more sensitive to indicate the effects of mefenacet and strain Y1 on functional diversity of the microbial communities. Shannon index （H） was more sensitive than the index of microbial community richness （S） to show the microbiological change in contaminated environment.