Effects of plant species coexistence on soil enzyme activities and soil microbialcommunity structure under Cd and Pb combined pollution
Yang Gao , Pei Zhou , Liang Mao , Yueer Zhi , Chunhua Zhang , Wanjun Shi
DOI:
Received June 02, 2009,Revised July 27, 2009, Accepted , Available online
Volume 22,2010,Pages 1040-1048
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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 o set 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 e ects of two plant species coexistence on soil microbial community and enzymes activities subjected
to Cd and Pb 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 di cult
to fully inhibit the phoshpatase activity, and urease responded similarly with phosphatase.
