模拟垂直流人工湿地不同木本植物根际细菌群落特征

Traits of bacterial communities in the rhizospheres of different woody plants in simulated vertical flow constructed wetland

为探讨植物种类对人工湿地中根际细菌群落结构特征分布的影响,以7种木本植物细叶水团花(Adina rubella)、南川柳(Salix rosthornii)、白棠子(Callicarpa dichotoma)、夹竹桃(Nerium oleander)、木芙蓉(Hibiscus mutabilis)、水蜡(Ligustrum obtusifolium)、大叶女贞(Ligustrum lucidum)为研究对象,运用16S rRNA细菌高通量测序技术,探究垂直流人工湿地木本植物根际微生物群落结构及其主要功能类群。结果表明:细叶水团花、水蜡根际菌群的多样性、丰富度与均匀度均高于其他5种植物,其根系能够更好地富集微生物。门水平上,变形菌门、厚壁菌门是木本植物平均相对丰度较高的门,其次为绿弯菌门、放线菌门和蓝藻门;属水平上,乳杆菌属、片球菌属、地杆菌属为木本植物的共有优势菌属;大叶女贞、白棠子、夹竹桃菌落组成差异显著,乳杆菌属、片球菌属、乳球菌属是引起7种木本植物样本间菌落差异的关键物种;7种木本植物根际硝化功能菌属丰度普遍较低,相对丰度范围为0.11%—1.06%;反硝化功能菌属的相对丰度范围为3.51%—10.40%,水蜡对于反硝化功能菌属的富集能力最强。基于实验得出,在模拟垂直流人工湿地条件下,根系水淹处理的木本植物为微生物反硝化作用营造了适宜的厌氧条件,使反硝化细菌在木本植物根际大量富集,供试的7种木本植物在适应水淹缺氧逆境胁迫的同时,仍能够保障人工湿地系统的氮去除能力。

The study was conducted to profile the community structure of rhizospheric microbes and investigate the key functional groups of seven woody plants including Adina rubella,Salix rosthornii,Callicarpa dichotoma,Nerium oleander,Hibiscus mutabilis,Ligustrum obtusifoliumand Ligustrum lucidum,by using high-throughput sequencing technology and the constructed wetland microcosmic reactor as the experimental model.The results showed that the diversity and evenness of bacterial community in the rhizospheres of Adina rubella and Ligustrum obtusifolium were higher than those of the other five species,and their root systems could better accumulate microorganisms.At the phylum level,Proteobacteria(34.7%)and Firmicutes(31.7%)were the phyla with the highest average relative abundance among 7 different woody plants,followed by Chloroflexus(7.4%),Actinomycete(6.8%)and Cyanobacteria(6.5%);at the genus level,Lactobacillus,Pediococcus and Geobacter were the common dominant genera of woody plants,with relative abundance of 11.5%,6.5%,and 2.5%,respectively.Principal component analysis showed that there were significant differences in the colony composition of Ligustrum lucidum,Callicarpa dichotoma and Nerium oleander.Lactobacillus,Pediococcus and Lactococcus were the key genera that caused colony differences among all woody plant samples.KEGG metabolic pathway analysis showed that the relative abundance of nitrobacteria in the rhizospheres of different woody plants was generally low,ranging from 0.11%to 1.06%;Ligustrum obtusifolium had the strongest ability to enrich denitrifying bacteria,with relative abundance of 3.51%-10.40%.Therefore,it can be concluded that anaerobic conditions promoted the process of microbial denitrification under the condition of vertical flow constructed wetland.Meanwhile,denitrifying bacteria could be enriched in the rhizospheres of woody plants.All the tested woody plants could guarantee the denitrifying ability of the constructed wetland system while adapting to the stress of anaerobic conditions.