Effects Of Bacillus Megaterium LY02 On The Remediation Of Heavy Metal Contaminated Soil By Lolium Perenne

Phytoremediation is becoming more and more popular in many heavy metal contaminated soil remediation techniques because of its low cost,simple operation and more sustainable development.However,there are many disadvantages in the specific implementation of phytoremediation,such as small biomass of repair plant,slow growth rate and low repair efficiency.In recent years,discovery and in-depth study of plant growth promoting rhizosphere bacteria provide a new way to solve this problem.In this paper,a plant growth promoting rhizosphere bacteria LY02 was isolated from rhizospheric soil of Lolium perenne through dilution-plate method.The biological characteristics of strain LY02 were also studied.And we combined it with Lolium perenne to repair Cu and Cd contaminated soil by pot experiment.Results indicates:(1)The total siderophore relative content of strain LY02 was 86.1%,which belonged to the high siderophore production bacteria.It was identified as Bacillus megaterum according to the analysis of physical and biological characteristics and 16 S rRNA gene sequences.(2)Fermented liquid of LY02 significantly increased the germination rate of Lolium perenne which was under the Cd stress.(3)Inoculate LY02 can significantly facilitate the growth of Lolium perenne which are under Cd and Cu stress.The biomass of Lolium perenne in the Cd contaminated,Cu contaminated and compound contaminated soil are increased by 40.5%,39.4% and 50%,respectively,and the difference was significant.(4)Inoculation significantly increased the content of available phosphorus and available Fe in rhizosphere soil of Lolium perenne.The increase of Cu contaminated soil was the largest among three kinds of soils,The contents of available phosphorus and available Fe were increased by 26.7% and 152.5% compared with the control group respectively,which improved the growth environment in heavy metal stress.(5)Inoculation increased the content of available heavy metals in three polluted soils.Among them,the content of available Cu was increased to 240.9 mg/kg in Cu contamined soil.(6)Inoculation promoted the uptake of heavy metals by Lolium perenne.In the single contamined soil,the uptake of Cd and Cu in Lolium perenne increased by 45.8% and 27.9% respectively,and the difference was significant.The results of the study clearly identified the role of Bacillus megaterium LY02 in the remediation of Cd and Cu contaminated soil by Lolium perenne,and it could provide a reference for the combination of microorganisms and plants to repair heavy metal contaminated soil.