【摘要】 根际微生物对维持土壤根际微域环境的活性和土壤有机污染物的自净、有毒重金属的迁移转化等发挥重要的作用。文章选用鄱阳湖优势湿地植物芦苇和苔草进行不同水文情势和外源铅锌下的室内试验,通过测定根际土壤微生物数量,探讨了水位和重金属Zn2+和Pb2+对湿地植物芦苇和苔草根际土壤微生物群落的影响。结果表明:外源锌(≥5 mg/kg)对芦苇根际细菌和真菌数量的影响表现为刺激作用,对放线菌数量的影响较为复杂;微生物对锌的敏感性大体上表现为放线菌>细菌>真菌。锌(≥5 mg/kg)对苔草根际细菌数量的影响表现抑制作用,对苔草根际放线菌和真菌的生长有刺激作用,但浓度高时(100 mg/kg)受到抑制,数量减少。总体上苔草根际细菌、放线菌和真菌较芦苇对锌更为敏感,表现为细菌>真菌>放线菌。水位对微生物数量的影响较大,相同铅离子浓度下淹水状态的细菌、放线菌和真菌数量显著高于湿润状态组;湿润状态处理组对铅的耐性大于淹水状态处理组;苔草根际细菌对铅的耐受性大于芦苇,芦苇根际的放线菌和真菌对铅的耐性大于苔草。更多还原

【Abstract】 Rhizospheric microbes play an important role in the activity maintaining of micro-environment in rihizosphere soil and in the self-purification of soil organic pollutants and the migration of toxic heavy metals. In this paper,two typical and dominant wetland plants including C. leucochlora Bunge and Phragmites communis from Poyang Lake were selected for pot experiments in different hydrological regimes and exogenous Zn2 +and Pb2 +,and the microbial quantities of bacteria,actinomycetes and fungi in rhizosphere soil were determined by traditional microbiological culture method. The influence of water levels and heavy metals Zn2+and Pb2+on the microbial colonies in the rhizosphere contaminated soils of two wetland plants were investigated. Results showed that exogenous Zn2+(≥5 mg/kg)stimulated and increased the amounts of rhizospheric bacteria and fungi for Phragmites communis,but its influence to the amount of actinomycetes showed more complex under different concentrations of zinc. The sensitivity of microorganisms to zinc generally showed actinomycete >bacteria >fungi.For C. leucochlora Bunge,exogenous Zn2+(≥ 5 mg /kg) caused the inhibition of rhizosphere bacteria numbers,but a stimulating effect on actinomycetes and fungi growth in Carex rhizosphere,they were inhibited when the concentration of exogenous zinc was higher than 100mg/kg. Generally,the microorganisms in rhizosphere of C.leucochlora Bunge are more sensitive to exogenous zinc than that of Phragmites communis with the order bacteria >actinomyces >fungi. Hydrologicalregimes had great influence on the quantity of microorganisms. Under the same concentration of Pb2+the amounts of bacteria,actinomycetes and fungi in waterlogged condition were significantly higher than that in moist state. The tolerance to lead of moist processing groups was bigger than that of waterlogged treatment groups. Rhizospheric bacteria of C.leucochlora Bunge had a higher tolerance to Pb2+than Phragmites communis,but for rhizospheric actinomycetes and fungi,the tolerance of Pb2+was Phragmites communis > C.leucochlora Bunge.更多还原