利用氧化亚氮还原酶基因 (nosZ) 评价人工湿地系统中的反硝化菌

应用人工潜流湿地净化微污染地表水,出水用于补给人工景观河.利用定量PCR测定了湿地植物根际土壤和景观河底泥中16S rDNA和nosZ的丰度,并采用PCR-DGGE技术考察了样品中含nosZ基因的群落结构及其相似性.定量PCR结果表明,潜流湿地及人工景观河16S rDNA、nosZ平均绝对丰度(以DNA计)分别为1.91E+07、1.26E+06和2.68E+07、8.37E+05 copies.ng-1,以干土计时分别为1.45E+11、9.31E+09和5.31E+11、1.45E+10 copies.g-1.景观河底泥中微生物总量和反硝化菌数量要高于湿地根际土壤,但是后者nosZ相对丰度(3.8%～10.1%)则明显高于前者(1.7%～4.1%).根际土壤和底泥样品聚类分析相似度低,根际土壤优势菌种大部分与红杆菌目(Rhodobacearales)、根瘤菌目(Rhizobiales)和伯克氏菌目(Burkholderiales)的细菌相似,而底泥的优势菌种均为不可培养的微生物.

Denitrifying Bacteria of Constructed Wetland System Based on Nitrous Oxide Reductase Gene (nosZ)

A horizontal subsurface flow constructed wetland was used to treat micro-pollution surface water and its effluent flowed into a landscape river as the water supplement. The abundance of the nitrous oxide reductase gene nosZ and 16S rDNA was investigated for the rhizosphere soil of the constructed wetland and the sediment of the landscape river by quantitive PCR. The diversity and similarity of denitrifiers were studied by using PCR-DGGE technique targeting the functional gene nosZ. The quantitive PCR results showed that the copy number of 16S rDNA and nosZ gene of the rhizosphere soil of the constructed wetland and the sediment of the landscape river were 1.91E+07, 1.26E+06 and 2.68E+07, 8.37E+05 copies·ng^-1(by DNA), and 1.45E+11, 9.31E+09 and 5.31E+11, 1.45E+10 copies·g^-1 (by dry soil), respectively. Generally, the total bacterial count and denitrifiers in the sediment of the landscape river was higher than that of the constructed wetland, but the relative abundance of nosZ of the latter (3.8%-10.1%) was significantly higher than that of the former (1.7%-4.1%). There was low similarity between the two niches in cluster analysis. The predominant species of rhizosphere soil were mainly contained Rhodobacearales, Rhizobiales and Burkholderiales, although the predominant species of sediment were uncultured bacteria.