Effects of plant species coexistence on soil enzyme activities and soil microbial community structure under Cd and Pb combined pollution

• Published in: Journal of environmental sciences (China) 2010-01, Vol.22 (7), p.1040-1048
• Main Authors: Gao, Yang, Zhou, Pei, Mao, Liang, Zhi, Yueer, Zhang, Chunhua, Shi, Wanjun
• Format: Article
• Language: English
• Subjects: Actinomycetes; Cadmium - metabolism; Cadmium - toxicity; DNA; ecological dose; Enzyme Activation - drug effects; enzyme activities; Enzymes - metabolism; heavy metal; Lead - metabolism; Lead - toxicity; Oxidoreductases - metabolism; Phosphoric Monoester Hydrolases - metabolism; Plants - metabolism; RAPD; Soil - analysis; Soil Microbiology; Soil Pollutants - metabolism; Soil Pollutants - toxicity; 土壤酶活性; 土壤镉; 复合污染; 微生物混合培养; 微生物群落结构; 植物物种; 物种共存; 铅污染
• ISSN: 1001-0742; 1878-7320
• DOI: 10.1016/S1001-0742(09)60215-1

The relationship between plant species coexistence and soil microbial communities under heavy metal pollution has attracted much attention in ecology. However, whether plant species coexistence could offset the impacts of heavy metal combined pollution on soil microbial community structure and soil enzymes activities is not well studied. The modified ecological dose model and PCR-RAPD method were used to assess the effects of two plant species coexistence on soil microbial community and enzymes activities subjected to Cd and Ph combined stress. The results indicated that monoculture and mixed culture would increased microbe populations under Cd and Pb combined stress, and the order of sensitivity of microbial community responding to heavy metal stress was： actinomycetes 〉 bacteria 〉 fungi. The respirations were significantly higher in planted soil than that in unplanted soil. The plant species coexistence could enhance soil enzyme activities under Cd and Pb combined. Furthermore, planted soil would be helpful to enhance soil genetic polymorphisms, but Cd and Pb pollution would cause a decrease on soil genetic polymorphisms. Mixed culture would increase the ecological dose 50% （ED50） values, and the ED50 values for soil enzyme activities decreased with increasing culture time. The dehydrogenase was most sensitive to metal addition and easily loses activity under low dose of heavy metal. However, it was difficult to fully inhibit the phoshpatase activity, and urease responded similarly with phosphatase.