丁草胺和毒死蜱复合污染对稻田土壤细菌群落多样性的影响

采用PCR—RFLP法研究了丁草胺和毒死蜱复合污染对土壤细菌多样性的影响。应用试剂盒提取土壤样品总DNA，以细菌的16SrDNA通用引物27F／1492R扩增16SrDNA片段，将扩增产物与T－载体酶连，转化大肠杆菌，建立16SrDNA克隆文库。阳性克隆子用限制性内切酶HhaI-RsaI消化，获得酶切指纹图。结果表明，通过双酶切分型，对照产生带型最多，有70种类型，其余处理OTU种类均比对照有所减少，分别减少了10、30和41种。在不同处理中其多样性存在差异。对照土壤环境中细菌种类最丰富，多样性最高，且基因型中无明显的优势类群，说明农药的外源喷施会引起土壤细菌多样性降低。处理Ⅲ的Shannon—Wiener指数、Simpson指数和丰富度都低于单一农药的处理，而均匀度非常高，说明这2种农药的复合施用对一些细菌的丧失会起协同作用，造成某些土壤细菌的富集。

Effect of Combined Pollution of Butachlor and Chlorpyrifos on Soil Bacteria Diversity in Paddy Field

The effect of combined pollution of butachlor and chlorpyrifos on the diversity of bacterial community in paddy field was studied by PCR-RFLP methods. Total DNAs of soil microorganisms were extracted by using Fast DNA SPIN Kit. The 16S rDNA fragments were amplified from the extracted soil DNAs by using bacterial universal pair primers 27F and 1492R. PCR products were ligated into the pMD 18-T Vector and transformed into Escherichia coil DH5α to construct a 16S rDNA clone library of the soil microbes. The fingerprints of positive clones digested with Rsa I and Hha I were analyzed. The results indicated that the control samples reduced 70 different kinds of band by using Hha I -Rsa I double digestion. The treated samples reduced 10, 30 and 41 kinds of band, separately. There were differences in diversity of different sample processing. The kinds of bacteria and diversity in control soil samples were rich, and there were not obvious dominant groups in the genotype. The treated soil by spraying pesticide would cause low diversity to bacteria. The Shannon-Wiener index, Simpson index and the richness of the processing Ⅲ were less than the single pesticide processing, and the uniformity was very high. Two kinds of pesticides together application had a synergistic effect on the loss of some bacteria and caused some soil bacteria enrichment.