重金属胁迫下大薸根际微生物的变化

The Rhizospheric Microbial Changes of Pistia stratiotes under Heavy Metal Stress

为了研究重金属对大薸根际微生物区系及氮循环细菌生理类群的影响,采用水培养方法,用4种重金属离子(Hg2+、Pb2+、Cd2+和Cr6+),在不同浓度下对大薸进行胁迫培养。结果表明,Hg2+、Pb2+、Cd2+和Cr6+对大薸根际微生物的影响,随微生物区系或生理类群和重金属的胁迫浓度不同而不同,Hg2+对放线菌、细菌、真菌的毒性最强,Pb2+次之。3类微生物对4种重金属的敏感性表现为放线菌>细菌>真菌。在4种不同重金属和不同浓度胁迫下,氨化细菌、硝化细菌、亚硝化细菌和反硝化细菌的变化有一定差异。

Aquaculture system were applied to study 4 different heavy metals Hg^2＋, Pb^2＋, Cd^2＋ and Cr^6＋ in different concentrations to cultivate Pistia stratiotes under stress to study the effect of heavy metals on rhizospheric microbial of P. stratiotes and the nitrogen cycle bacteria population. Results showed that the effects of Hg^2＋ , Pb^2＋ , Cd^2＋ and Cr^6＋ to P. stratiote rhizospheric microbes were different along with the changes of stress concentration of the metals. Hg^2＋ had the strongest toxicity on actinomycetes, bacteria and fungi, the following was Pb^2＋. The sensitivity reflection order of 3 microbes to 4 heavy metals was actinomycetes 〉 bacteria 〉 fungi. The changes of ammonification bacteria, nitrobacteria, nitrosobacteria and denitrifying bacteria were different under 4 different heavy metals and different stress concentrations.