| Plant-mycorrhizal fungi combined remediation of heavy metal contaminated soil has become one of the most promising ecological remediation methods for its green,low consumption and sustainability.In order to understand the potential of bioremediation of Pb/Zn heavy metal contaminated soil by ectomycorrhizal fungi(Suillus luteus)and masson's pine(Pinus massoniana)symbiotic system,and explore its repair mechanism,providing theoretical basis and technical guidance in the practical application of heavy metal contaminated soil.Masson's pine inoculated with and without ectomycorrhizal fungi were designed in two polluted areas with two different levels of Pb/Zn pollution degree in soil,the low heavy metal contaminated soil inoculated with ectomycorrhizal fungi(EA),the low heavy metal contaminated soil inoculated without ectomycorrhizal fungi(NEA),the high heavy metal contaminated soil inoculated with ectomycorrhizal fungi(EB),and the high heavy metal contaminated soil inoculated without ectomycorrhizal fungi(NEB),while soil without ectomycorrhizal fungi planted in the area without heavy metal contamination was sampled as control.The changes of growth potential,heavy metal and main nutrient absorption and transport characteristics,photosynthetic characteristics,soil physical and chemical properties and main soil enzyme activities of masson's pine seedlings in Pb/Zn mining area were observed,and the correlation between them was analyzed,and the results were followed:(1)There were obvious differences in the growth of masson's pine seedlings inoculated with and without ectomycorrhizal fungi in heavy metal contaminated soil.The annual growth rate,annual branch length and ground diameter of masson's pine seedlings inoculated with ectomycorrhizal fungi were higher than that of masson's pine seedlings inoculated without ectomycorrhizal fungi and control treatments in high and low heavy metal contaminated soil,and the difference of annual growth and ground diameter is obvious.The diameters of masson's pine seedlings inoculated with ectomycorrhizal fungi in high and low heavy metal contaminated soil increased by 18.3%and 68.3%,respectively,compared with that of masson's pine seedlings inoculated without ectomycorrhizal fungi.(2)The accumulation and transportation of heavy metals were affected by masson's pine seedlings inoculated without ectomycorrhizal fungi.In the soil with the same degree of contamination,the accumulation of heavy metals Pb,Zn,Cd,Cu and Mn in the roots of masson's pine seedlings inoculated with ectomycorrhizal fungi increased by 1-5 times compared with that of masson's pine seedlings inoculated without ectomycorrhizal fungi,and the transfer coefficient decreased.Among them,transfer coefficient(TF)of Pb in masson's pine seedlings inoculated with ectomycorrhizal fungi in high heavy metal contaminated soil decreased by nearly 50%.(3)The absorption and accumulation of nutrients improved in masson's pine seedlings inoculated with ectomycorrhizal fungi in high heavy metal contaminated soil.N content of masson's pine inoculated with ectomycorrhizal fungi increased by 30%in low heavy metal contaminated soil,P content increased by 80%in high heavy metal contaminated soil,and Se content increased by 33%and 5%in low and high heavy metal contaminated soil,respectively.(4)Photosynthetic characteristics of masson's pine seedlings inoculated with ectomycorrhizal fungi on heavy metal contaminated soil were different from those inoculated without ectomycorrhizal fungi.The net photosynthetic rate of masson's pine seedlings inoculated with ectomycorrhizal fungi on the low and high heavy metal contaminated soil was 25.9%and 44.5%higher than that of masson's pine seedlings inoculated without ectomycorrhizal fungi.Meanwhile,transpiration rate of masson's pine seedlings inoculated with ectomycorrhizal fungi was higher than that of without ectomycorrhizal fungi.Photosynthetic rate and transpiration rate were positively correlated with the accumulation of Pb and Zn in masson's pine seedlings.(5)The physicochemical properties of rhizosphere soil were improved inoculated with ectomycorrhizal fungi.The water content in low and high heavy metal contaminated soil increased by 84%and 45%inoculated with ectomycorrhizal fungi,respectively.The contents of available N,P,K,C/N and the activities of urease and alkaline phosphatase in soil were significantly increased.Soil water content was positively correlated with Se,N and P contents in plants,and urease and alkaline phosphatase were closely correlated with the available N and P contents in soil.In conclusion,ectomycorrhizal fungi can improve the physicochemical properties of contaminated soil,promote the absorption of nutrient elements by plants,reduce the transfer of heavy metal elements to the aboveground,alleviate the toxicity of heavy metals,promote the growth of masson's pine seedlings,and enhance the remediation efficiency of heavy metals in the Plant-mycorrhizal fungi symbiotic system. |
PDF Full Text Request