采用PCR-DGGE技术研究处理农田退水组合人工湿地微生物群落特征

A PCR-DGGE study of bacteria community diversity in the constructed wetland treated with agricultural return flow

以种植美人蕉和旱伞竹的复合垂直流人工湿地(MIL)系统的基质(分子筛、陶粒和碎石)及表流人工湿地的基质土壤为材料,采用PCR-DGGE技术研究处理农田退水的湿地中微生物群落结构的差异及其优势菌群.结果显示,MIL系统上行池中种植美人蕉、旱伞竹和不种植物对照3个处理的表层水样和上层碎石基质以及表流人工湿地3个处理的基质土样的可操作分类单元OTU(Operation Taxonomy Unit)数目都比较多(12-14),说明其微生物种类较多,微生物多样性较高,其优势种群主要为Uncultured Xylella sp.、Uncultred bacterium以及Uncultured Tolumones sp.和Acidovorax;MIL系统上行池下层的陶粒和分子筛基质的OTU数目以对照和种植旱伞竹的较高(6-11),而种植美人蕉处理最少(4-5),呈现微生物种类少、微生物多样性较低的特点,其优势种群主要有Uncultured Xylella sp.、Uncutured soil bacterium和Uncultured Sphingomon adacsas.这些结果表明垂直复合湿地系统选择种植美人蕉能提高其下层基质还原性,降低细菌多样性,有利于硝态氮的还原去除.

This research aimed to understand the similarities and differences of microbial community structure of the constructed wetlands with different plants as well as the dominant flora in the wetlands. The matrix （molecular sieves, ceramsite and gravel） and surface water samples were taken from the integrated vertical flow constructed wetland （MIL） system with Canna indica and Cyperus alternifolius, and ~oil samples taken from surface flow wetland. The samples were treated with agricultural return flow and analyzed by PCR-DGGE. The results showed 12 to 14 bands of OTUs of the stone matrix and water samples from the upper of the up-flow pool in MIL system and the soil samples from surface flow wetland in all three treatments, which indicated great number of microorganisms species and high microbial diversity. The dominant flora were uncultured Xylella sp., uncultred bacterium, uncultured Tolumones sp. and Acidovorax. The OTU numbers of ceramsite and molecular sieve were slightly higher in the MIL systems pool planted with C. alternifolius and the blank control （6-11 bands） than in the systems planted with C. indica （4 to 5 bands）, showing the less species and lower microbial diversity in the latter. The dominant flora were uncultured Xylella sp., uncultured soil bacterium and uncultured Sphingomon adacsas. These results indicated that the integrated vertical flow constructed wetland system planted with canna could enhance the reduction in the base matrix and decrease the bacterial diversity, beneficial for the removal of nitrate nitrogen.