文档介绍：Chapter5MicrobialEcologyMicrobial Ecology?anismsinsoil,water,anismsacttochemically soil?anismsas ,fungi,algae, protozoaand virusesmakeupthismicroscopicmenagerie,whichmayreachatotal ofbillionspergram.?Thegreatdiversityofthemicrobialfloramakesit .?ountstheoreticallyshouldpermitenumerationofallexcepttheviruses,butthis techniquealsohas itslimitations,especially,anisms.?Veryoftenthemicrobiologicalanalysisofsoilis concernedwiththeisolation , differential media, . The Rhizosphere?Rhizosphere:Theregionwherethesoilandrootsmakecontactis designatedtherhizospherewhichischaracterizedby azoneofincreasedmicrobiologicalactivity.?Themicrobialpopulationonandaroundrootsisconsiderablyhigher thanthat ofroot-,and theirgrowthis enhancedbynutritionalsubstancesreleasedfromtheplantroots,.,aminoacids,vitamins,andothernutrients.?Thegrowthoftheplant is influencedbytheproductsofmicrobialmetabolism thatarereleasedinto soil. It hasbeenreportedthataminoacid-requiringbacteriaexistinrhizosphereinlargernumbersthan in theroot- anismsoftherhizoshereismoreactivephysiologicallythanthat of non-rhizospheresoil.?plexbiological system,andthere is agreatdealyettobelearnedabouttheinteractionswhich anismsintimatelyassociatedwithitsroot system.?Electron—anismsdirectlyontheroot surfaces.