Zhang Cuiping, Wang Bei, Dai Xiaoyan, Li Shuying, Lu Guangqiu, Zhou Yuanqing
Research Center for Pollution Control and Ecological Restoration, Yuxi Normal University, Yuxi, 653100, People's Republic of China.
Institute of Ecology and Geobotany, Yunnan University, Kunming, 650091, People's Republic of China.
Environ Sci Pollut Res Int. 2017 Apr;24(12):11483-11492. doi: 10.1007/s11356-017-8463-1. Epub 2017 Mar 18.
Vertical flow constructed wetlands (VF CWs) are considered to be effective for treating organic pollutants. The rhizosphere of macrophytes such as Phragmites sp., Typha sp. serves as an active and dynamic zone for the microbial degradation of organic pollutants. However, it is still not clear how soil bacterial communities respond to macrophytes and pollutants during the process. For this purpose, the seedlings of Phragmites australis and Typha angustifolia were planted respectively in the VF CWs added with HCB at a dose of 2 mg/kg. During 96 days of cultivation, we monitored hexachlorobenzene (HCB) removal efficiency by GC/MS and the structure of the rhizosphere bacterial communities in the different VF CWs by denaturing gradient gel electrophoresis (DGGE), and constructed bacterial clone library based on PCR-amplified 16S rRNA gene. As expected, the rhizosphere bacterial communities also remained insensitive to HCB exposure in the wetland soil. The diversity of these microbes presented two stages, from the varied up and down to equilibrium in the entire experimental period. Molecular analysis revealed that the phylum Firmicutes dominated over the bacterial communities. The genera that increased under HCB stress included the well-known HCB-degrading bacteria (Pseudomonas sp. and Alcaligenes sp.) and other common bacteria found in contaminated soil but with lesser known practical functions (Burkholderia sp., Lysinibacillus fusiformis, and Bacillus cereus). Furthermore, there was a certain variance in the relative abundances of the bacterial phyla and HCB removal efficiency among different VF CW treatments. The degradation of HCB in T. angustifolia microcosms was faster than that in P. australis and unvegetated wetlands, and the highest bacterial diversity and richness was found in the VF CWs comprising T. angustifolia.
垂直流人工湿地（VF CWs）被认为对处理有机污染物有效。芦苇属、香蒲属等大型植物的根际是有机污染物微生物降解的活跃动态区域。然而，在此过程中土壤细菌群落如何响应大型植物和污染物仍不清楚。为此，将芦苇和狭叶香蒲的幼苗分别种植在添加了2 mg/kg六氯苯（HCB）的VF CWs中。在96天的培养期间，我们通过气相色谱/质谱联用仪（GC/MS）监测六氯苯（HCB）的去除效率，并通过变性梯度凝胶电泳（DGGE）监测不同VF CWs中根际细菌群落的结构，基于聚合酶链反应（PCR）扩增的16S rRNA基因构建细菌克隆文库。正如预期的那样，根际细菌群落在湿地土壤中对HCB暴露也保持不敏感。这些微生物的多样性呈现出两个阶段，在整个实验期间从上下波动到平衡。分子分析表明，厚壁菌门在细菌群落中占主导地位。在HCB胁迫下增加的属包括著名的HCB降解细菌（假单胞菌属和产碱菌属）以及在污染土壤中发现但实际功能鲜为人知的其他常见细菌（伯克霍尔德菌属、梭形赖氨酸芽孢杆菌和蜡样芽孢杆菌）。此外，不同VF CW处理之间细菌门的相对丰度和HCB去除效率存在一定差异。狭叶香蒲微宇宙中HCB的降解速度比芦苇和无植物湿地中的快，并且在包含狭叶香蒲的VF CWs中发现了最高的细菌多样性和丰富度。
