生活污水对土壤及湿地植物根际细菌群落的影响

为探究生活污水对土壤及湿地植物根际细菌群落丰富度和多样性的影响,选择芦苇、水葱、千屈菜、扁秆藨草和长苞香蒲5种湿地植物单独种植,利用PCR-DGGE技术,分别测定试验土壤ck1、浇灌污水的土壤ck2、浇灌自来水的湿地植物ck和污水处理湿地植物根际的细菌群落。结果表明:污水处理植物根区土壤细菌种群丰富度和多样性指数最高,其次是污水浇灌的土壤ck2和自来水浇灌的植物ck,试验土壤ck1的最低。试验测定的优势细菌如下:ck1有根瘤菌属(Rhizobium)和鞘氨醇单胞菌属(Sphingomonas);ck2有鞘氨醇单胞菌属(Sphingomonas)、根瘤菌属(Rhizobium)、节杆菌属(Arthrobacter)和赤杆菌属(Erythrobacter);ck有黄杆菌属(Flavobacterium)和节杆菌属(Arthrobacter);污水处理植物根区有节杆菌属(Arthrobacter)、梭菌属(Clostridium)、硫酸盐还原细菌(Sulfate-reducing bacterium)、牦牛瘤胃菌(Proteiniclasticum)和黄杆菌属(Flavobacterium)。综上认为,污水浇灌的土壤ck2和污水处理5种湿地植物根际细菌群落多样性均高于自来水浇灌植物ck和试验土壤ck1,湿地植物根际细菌群落随植物种类不同差异较大,其中污水处理千屈菜根区细菌种群丰富度最高,其次是水葱、芦苇和长苞香蒲扁,扁秆藨草根区细菌种群丰富度最低。浇灌污水和种植湿地植物均明显改变了土壤中的细菌群落结构和多样性,污水对土壤细菌群落多样性的影响作用高于植物。

Impacts of domestic sewage on community structure and diversity of bacteria in the soil and rhizospheres of five wetland plants

The structure and diversity of bacterial communities were studied within the soil and within the rhizospheres of five wetland plants treated with tap water and sewage water using the PCR-DGGE technique. Results indicate that the dominant bacterial communities undergo a shift both within bare soil, and within the wetland plant root zone with the addition of sewage water, The bacterial community diversity index was highest within the rhizospheres of wetland plants that were treated with sewage water, followed by the soil without plants that was treated with sewage water, and then within the root zone of wetland plants immersed in tap water. The bacterial community diversity index was lowest in the un-amended experimental soil used for plant culture. The dominant phyla of the bacterial communities were analyzed by denaturing gradient gel electrophoresis(DGGE) and sequencing of partial 16S rRNA genes. There were eight genera of bacteria detected in our study overall. Within the un-amended experimental soil treatment, Rhizobium and Sphingomonas were the dominant genera; in the treatment with just soil and sewage, Sphingomonas, Rhizobium, Arthrobacter and Erythrobacter were the dominant genera; within the root zones of the wetland plants in tap water, Flavobacterium and Arthrobacter were the dominant genera; and within the root zones of the wetland plants in sewage water, Arthrobacter, Clostridium, Sulfate-reducing bacteria, Proteiniclasticum and Flavobacterium were dominant. This study provides evidence that sewage may promote the growth of diverse microbial communities in soil and within the rhizospheres of wetland plants.