Effects Of AM Fungi On Growth And Physiological Characteristics Of Medicago Sativa In Coal Mine Waste Substrate Of Coal-mining Subsidence Land

The ecological environment of mining are was further deteriorated with the continuous exploitation of coal resources.The surface subsidence leads to the destruction of soil physical structure,soil water content declined,nutrient elements leaks and soil desertification,which limits the growth of vegetation in the mining area.To improve the growth and survival race of plants in coal mine waste,potting experiment in greenhouse was carried out to explore the effects of single and mixed inoculation with AM fungi?Funneliformis mosseae,F.m and Claroideoglomus etunicatum,C.e?on the mycorrhizal colonization rate,mycorrhizal dependency,aboveground growth index,root morphological index and root activity,antioxidant system index,osmotic adjustment substances,NO₃^--N content,P content and chlorophy?content of Medicago sativa in different compound substrates.The compound substrates are formed by mixing coal gangue?CG?,fly ash?FA?and sandy soil?SS?mixed in different proportions?T1:CG:FA:SS=75%:25%:0%,T2:CG:FA:SS=60%:25%:15%,T3:CG::FA:SS=45%:25%:30%,T4:CG:FA:SS=30%:25%:45%?and T5:CG:FA:SS=0%:0%:100% was taken as control.Results showed that:?1?The AM fungi formed a good symbiotic relationship with M.sativa?s root under five different compound substrates and the mycorrhizal colonization rate was between 17.28%and64.31%.However,the maximum mycorrhizal colonization rate and mycorrhizal dependency after inoculation of F.m+C.e?F.m:C.e=1:1W/W??64.31%and 86.24%?occurred in T4substrate.?2?Inoculation with AM fungi increased height,stem diameter,leaf area and biomass of M.sativa to some degrees,and the effects of mixed inoculation were better than that of single inoculation.Growth of plant roots were inhibited by excessively adding coal mine solid waste.However,after inoculation with AM fungi,the total length,surface area,volume and activity of M.sativa?s root were significantly increased,and the average diameter of M.sativa?s root was decreased.?3?With the increase of content of coal gangue and coal fly ash,the POD activity,SOD activity,CAT activity,and ASA content in the leaves of M.sativa showed a tendency to decrease but the MDA content and O₂^-production rate were significantly increased.The same inoculation treatment,the antioxidant activity of M.sativa?s leaves were increased to different degrees in different substrates.Inoculation with AM fungi significantly increased the activity of POD,SOD,CAT and ASA content,meanwhile,MDA content and O₂^-generation rate in leaves of M.sativa were significantly decreased compared to non-AMF treatment.The mycorrhizal ecological effects of AM fungi could be improved by substrate stress to a certain extent.?4?The relative permeability of cell membrane increased and soluble sugar content,soluble protein content,NO₃^--N and P content decreased in coal mine solid waste substrates.However three inoculation treatments significantly decreased relative permeability of cell membrane and significantly increased soluble sugar content,soluble protein content,NO₃^--N and P content.This indicated that AM fungi had effectively alleviate the adverse effects of plant cells and improve the osmotic regulation ability under coal mine solid waste substrates.?5?The photosynthesis of M.sativa?s leaves was inhibited by coal gangue and fly ash.Different substrate treatment,with the increase of content of coal gangue and coal fly ash,chlorophy?content of M.sativa showed a tendency to decrease.Comparative effects of different inoculation treatments on content of chlorophy?a,chlorophy?b,toal chlorophy?and carotenoid of M.sativa?s leaves with were F.m+C.e>C.e>F.m>non-AMF.Therefore,inoculation of AM fungi contribute to the synthesis and accumulation of leaf photosynthetic pigments,increased biomass,growth of M.sativa and enhance the ability to resist stress in coal mine waste substrate of coal-mining subsidence land.