论文部分内容阅读
To combine phytoremediation plants and microorganisms is a promising method of repairing heavy metal contaminated soil.In this study,two manganese-tolerant strains isolated from Mn slag and identified as B.cereus HM5 and B.thuringiensis HM7.These two Bacillus spp.species have the ability to dissolve phosphorus,produce IAA and iron carrier.A pot experiment of Broussonetia papyrifera was conducted to test the growth,root structure and activity,and accumulation of Mn with B.cereus HM5 and B.thuringiensis HM7 inoculation under the pollution of heavy metal Mn(5 mmol/L,50 mmol/L,wild Mn slag).Besides,the physiological and biochemical characteristics of the leaves and the effects of the soil environment were observed.The results showed that the biomass,total root length,surface area,crossings,tips,forks and root activity of B.papyrifera with inoculation were higher than those of the uninoculated control group.The inoculation of these two Bacillus spp.increased the absorption of Mn by B.papyrifera and the concentration of Mn in the aerial parts of plants,indicating that the two strains could promote the growth of B.papyrifera and the accumulation of Mn.In addition,microbes reduced MDA content,CAT,SOD,and POD activities in leaves,suggesting that the two Bacillus spp.reduced Mn-induced oxidative stress.The principal component analysis showed that the added Bacillus strain prefer to promote plant root function maintenance and improve soil environment,rather than direct adsorption of heavy metals.These observations indicated that B.cereus HM5 and B.thuringiensis HM7 were valuable microorganisms,which could effectively improve the repair efficiency of B.papyrifera under Mn-contaminated soil.