简介：Thecharacteristicsofarbuscularmycorrhizalfungal(AMF)communitystructureinvarioussoildepthsandgrowingseasonsofwatermelon(Citrullusvulgaris)grownincommercialgreenhousesinDaxingofBeijingandWeifangandLaiyangofShandong,Chinawereinvestigatedusingbothmorphologicalidentificationanddenaturinggradientgelelectrophoresis.Thesampledsoilshadbeenusedforcontinuousgreenhouseproductionofwatermelonfor0,5,10,15,or20years.Glomusclaroideumwasthedominantspeciesinthegreenhousesoilsplantedfor5,10,and15yearsinLaiyang,whileGlomusmosseaeandGlomusetunicatumweredominantinthenearbyopenfarmlandsoil.Sorenson'ssimilarityindexofAMFcommunitycompositionrangedfrom0.67to0.84inthesoilsplantedfor5years,andfrom0.29to0.33for20yearsamongthethreelocations.Sporeabundance,speciesrichness,andtheShannonindexwerehighestnearthesoilsurface(0-10cm)anddecreasedwithsoildepth,andhigherinJuneandOctoberthaninAugustandDecember.CanonicalcorrespondenceanalysisshowedthatavailablePandthenumberofyearsthatsoilhadbeenusedforgreenhouseproductionwerethemainfactorscontributingtothevarianceofAMFcommunitycomposition.ItwasconcludedthatthecommunitystructureofAMFwasmainlyinfluencedbysoilavailablePandplantingtimeofwatermelonaswellasbysoildepthandseasonalvariationinthecommercialgreenhouse.