K-release and weathering of muscovite by Cenococcum geophilum

Abstract:

Abstract:［Objective］To use efficiently the insoluble K-bearing minerals in forest soil as nutrients for plant growth，we studied the weathering mechanism of muscovite by ectomycorrhizal fungi．［Methods］Cenococcum geophilum，Paxillus involutus，Laccaria bicolor，Pisolithus tinctorius，and Suillus tomentosus were used to dissolve muscovite in three culture mediums． Furthermore，K release from muscovite，biomass，remaining glucose，pH value andorganic acids were measured during the 21-day incubation of C．geophilum in Modified Melin-Norkrans (MMN) culture medium．We also compared K release amounts，organic acids and polysaccharides in external environment with those in micro-environment after 15-day and 21-day bioleaching．The weathering phenomenon on muscovite surface was observed by Scanning Electron Microscope (SEM).［Results］Among five ectomycorrhizal fungi，C．geophilum showed the best K-releasing ability in MMN culture medium．Fungal biomass，remaining glucose and pH value had significantly effects on K release．With the aid of exopolysaccharides，the hypha adhered to the mineral surface forming the micro-environment．In the microenvironment，organic acids were concentrated to promote K-release from muscovite，and obvious weathering marks on muscovite surface were found by SEM image．［Conclusion］Ectomycorrhizal fungi could weather muscovite to provide Ksolubilizing microbial resource for plant growth，and the synergism action of hyphae，organic acids and polysaccharides would accelerate K mobilization.