土壤与生物学论文 13页

土壤生物学期末作业姓名:卢鸿佳学号:201430320615专业班级：14计算机科学与技术6班InsightsintotheresponsesofsoilmicrobialcommunitytotheenvironmentaldisturbancesLIJingl,2,LIUYurongl,HEJizhengl,ZHENGYuanmingl,*1.StateKeyLaboratoryofUrbanandRegionalEcology,ResearchCenterforEco-EnvironmentalSciences，ChineseAcademyofSciences,Beijing1000852•UniversityofChineseAcademyofSciences,Beijing100049Received13August2012;receivedinrevisedform19September2012;accepted7October2012Abstract:Soilisunderincreasingenvironmentalpressuresthatcanalteritscapacitytofulfillessentialecosystemfunctions.Microorganismsplayimportantrolesinmaterialandenergyflowsofecosystem-Thus,itisessentialtounderstandhowsoilmicroorganismsrespondtoenvironmentaidisturbances.Soilmicrobialcommunitydiversitydeterminedsoilecosystemstabilitytoagreatextent.Manystudiesdemonstratedthatsoilecosystemwouldbemorestablewithhigherbiodiversity.Inthispaper,wesummarizedtherecentprogressintheresponses(resistaneeandresilience)ofsoilmicrobialcommunitiestoenvironmentaistressesandtheunderlyingecologicalmechanisms.Whennewmicrobialcommunityadaptedtothestresses,theresistaneeandresilienceofthesoilmicrobialcommunitywouldbechangedaccordingly.Meanwhile,resistanceandresilieneetodisturbancemightalsovarybetweenmicrobialcommunities.Thesevariationsofsoilmicrobialcommunitydependedonnotonlytheresistantmicrobesandtheirhorizontalresistantgenestransfer,whichledtotheshiftincompositionanddiversityofsoilmicrobialcommunity,butalsothecompositionandfunctionalredundancyofthemicrobialcommunity.Functionalredundancywithinacommunitymightactasabufferagainstfunctionmutabilityresultedfromthebiodiversityloss.Therefore,investigationontherelationshipbetweensoilecosystemstabilityandmicrobialdiversitywouldrevealthedrivingmechanismsofmicrobialadaptiontotheenvironment，andbehelpfultoprovidemeasurestoquantifyingsoilmicrobialfunctionandbiodiversity.Keywords:environmentaidisturbances;soilmicrobialdiversity;resistance;resilienee;stabilityl.lntroductionSoilisanimportantpartoftheEarth'secosystems,terrestrialecosystemsandhumansurfacemostcloselyspheres,soilecosystemstabilityisimportantforecologicalsafety.Soilmicrobialhugeandvariety,participatedinbiogeochemicalcyclingofelements,theecologicalfunctionofplantgrowth,climateregulationandotherterrestrialecosystemsplaysanirreplaceablerole(Gansetal.,2005).TheybearatemporarydisturbanceorstressmayreflecttheIong-termabilityofthevariousprocessesofecosystemstabilitytosomeextent,soitisnecessarytostudymicrobestoenvironmentaiconditions\nenvironmentalstressescausedbythechangeinresponsetomake,particularlyinenvironmentaiissuesincreasinglyprominenttoday,moreandmoreresearchhasfocusedontherelationshipbetweensoilmicrobialsoilecosystemfunctionandstabilitybetweenthe(Gansetal,2005;.Loreauetal,2010;.Girvanetal,2005.).Althoughstudieshaveshownthatdecreasedsoilmicrobialdiversityisaseriousthreattotheecosystem(Griffthsetal.,2000),butduetothecomplexityofthesystemitself,thesoil,microbialecologistsdescribedifficulttoquantifysoilmicrobialplayedagainstenvironmentaistresseffectontheunderstandingofthemechanismofwhichisstillrelativelyvague・MeCann(2000)believesthattheabilitytorespondtochangesinthesystembyitselfoutsideinterfereneecontainsbothresistaneeandresilience.Resistancereferstothesystemitselfhastoresistnaturalorman-madeenvironmentaifactorsstressandabilitytomaintaintheoriginalstateofconstant,resilieneereferstothesystembynaturalormadeenvironmentaifactorsstresstheabilitytoreturntoitsoriginalstate(LiFangetal.,2009).Thetheoryputforwardtoexplaintherelationshipbetweenmicrobesandenvironmentalstressnotedagooddirection.Therefore,thisarticleintendstodiscussthefollowingthreeaspects:①therelationshipbetweensoilmicrobialdiversityandecologicalstabilityofthesystembetween;②theimpactofenvironmentalstressonthesystemstability③soilecologyMicrobialdiversityinitsresponsetoenvironmentalstressContactbetween.Onthebasisofsoilmicrobialsummaryofenvironmentalresearchprogressonmechanismofstressresponse,trytoputforwardtheresearchcurrentproblemsandfuturedevelopmentdirection.2.Soilmicrobialdiversityandsoilecosystemstability2.1MicrobialcommunitydiversityHighmicrobialabundancesothatittakesprimacyinecosystemservices,onlythebacterialandarchaealorganismcompositioncontainsmostofthenitrogen,phosphorusandalmosthalfofthecarbonandmicrobialmetabolismdrivenmostecologicalProcesses(Allisonetal.,2008),Thus,microbesplayaveryimportantroleintheecosystemmaterialcirculationandenergyflowprocess・Althoughthemicroorganismsmaintainecosystemfunctionsithasanimportantrole,buttheinternalmechanismoftheprocesshasyettoclear.Inadditiontothelackofmethodological,themainreasonishighmicrobialdiversity.Accordingto(2002)theassumptionLoreau,toreducebiodiversitydeclinewillleadtoecosystemstability,andhighdiversityofecosystemsduetothepreseneeofmoremicro-organismstoadapttoenvironmentaichangestableecosystem・Withthedevelopmentofmolecularbiologytechnology,peopleonthestructureanddiversityofmicrobialcommunitiesinmoredepth,andanewunderstandingofthespeciesisdividedsothattherelationshipbetweenthestudyofmicrobialdiversityandecosystemfunctioninghasalsobeenanewbreakthrough(Griffthsetal,2000,2001;.Heetal,2009)..Speciesdiversityofspeciesrepresentstheevolutionofthespatialextentandecologicaladaptationtoaparticularenvironment,isthemainproductoftheevolutionarymechanism,sothespeciesisconsideredtobethemostsuitableforthestudyoflifelevelsofbiodiversity,butalsotherelativelevelsofthemoststudied(LeeBo,2000).Morecurrentresearchisadiversity(withincommunitiesorhabitatsbiodiversity),PDiversity(bornbetweencommunitiesorbetweenhabitatsbiodiversity),ydiversity(geographicalareaofbiodiversity).(1)adiversity:morecommonadiversityindexineludingspeciesrichnessindex,Shannon-Wienerindex,Simpsonindex,evennessindex(J).(2)Pdiversity:Pdiversitysimilarmeasure(dissimilarity)indexiscurrentlythemostcommon,accordingtothecharacteristicsofdata,mainlySrensenindexandJaccardindexforbinarydata,theamountofdatausedBray-Curtisindexandtheirvariousmodifications(ChenShengbinetal.,2010).(3)ydiversity:adiversitywhichhasthesamefeatures,buttheapplicationofdifferentscales(Rae,2000),ydiversitydimensionisgreaterthanadiversityandpdiversity.\n2.1SoilmicrobialdiversityandecosystemstabilityThestabilityofecosystems(ecosystemstability)referstotheresistaneeofecosystemstoenvironmentaichanges,interference,andtheabilitytomaintainsystembalance(MeCann,2000).Itisnotonlytheecosystemstructure,functionandevolutionoffeatures,butalsotothestrengthandcharacteristicsoftherelevantexternalinterference,ineludingresistaneestabilityandresilieneestability(MeCann,2000).Microbialdiversity(microbialdiversity)meanstheintra-speciesofmicroorganismsatthegenetic,speciesandecosystemlevelchangesandmicrobialcommunitiesandspeciesdiversity,includingphysicalfunctionaldiversity,diversityandthegeneticmaterialofcellsdiversityAndsoon,inessence,itstemsfromgeneticdiversity.Microbialdiversityinmaintainingsoilquality,animportantroleinmaintainingstabilityandhealthofterrestrialecosystemshasattractedmuchattention,inwhichtherelationshipbetweenmicrobialdiversityandecosystemstabilityamongecologistshasbeenthehottopicofconcern・Manystudiesshowthatdiversityofcommunitieswillhelpimprovetheecosystemstability,productivityandsustaiinability(Gilleretal,1997;.Dangetal,2005;..Setalaetal,2004),fullystressedmicrobialdiversitythelevelofecosystemfunctionmaintainedanimportantrole(Belletal.,2005).AsGriffithsetal.(2000)withchloroformsoilfumigationusingdifferentmethodstoreducethemicrobialdiversity,theresultsshowthelowestrateofdecompositionofsoilmicrobialdiversityofplantheatstressandstressresilieneeofcopperminimum.SetandMeClean(2004)studiedtherelationshipbetweenspeciesandecosystemstabilityofsoilfungiinsoil,experimentsweresetupsixfungaldiversitygradient,whichcontainsthehighestdiversityofhandling43Fungi,withstanddroughtaddwaterimmediatelyafterstressfoundtocontain43communitiesdealwithfungalbiomassandfungalrespirationratesuptothemaximum,toprovethatthehighermicrobialdiversityinhigherecosystemstabilitytheory•Agenerallyanimportantroleinthestudyofbiologicaldiversitytoecosystemfunctioningwillconsiderchangesinspeciesrichness,butinaddition,othercomponentssuchasevenness(ie,arelativelylargenumberofspecies)isalsoveryimportantindex・Therefore,weshouldmeasurethestabilityofthebiologicaldiversityofecosystems,consideringvariousindicators•Wittebolle(2009)studiedtheinflueneeofdenitrifyingbacteriacommunityevennessofecosystemstability,andinallcasesaretreatedthesamerichnessinthefaceofsaltstress,ecosystemstabilityanddenitrifyingbacterialcommunityactivityuniformityiscloselyrelatedtothebacterialcommunitythatishighlynon-uniformifasmallport!onofthespeciesoccupiesmostofthecompositionofthecommunity,thenaftersaltstressresistanceandresilieneebacterialcommunitiesarelow.Thismeansthattheresearchcommunityneedstoconsidernotonlythediversityofspeciesrichnessalsoneedtoexaminetheevennessofinfluenee.3Influencesofenvironmentaistressesonsoilecosystemstability3.1InsightsintotheresponsesofsoilmicrobialcommunitytotheenvironmentalDisturbancesenvironmentaistressreferstoenvironmentalpressureontheorganisminwhichthesurvivalofthestatearisingoutoforontheecosystemDevelopmentproduceabindingeffectenvironmentalimpacts,themainformofcoldinjury,drought,saltstressandUV-Bradiation(Rae,2000).Forthepurposesofsoilecosystem,soilpollutionsincetheIndustrialRevolutionhasbecomeoneofthemostimportantsoilecosystemenvironmentaistress,\nespeciallyheavymetals・Long-termheavymetalpollutionwillseriouslyaffectthenumberandactivityofsoilmicroorganisms,microbialcommunitystructurechangedtherebyaffectingthefunctioningofthesoilecosystem(Tsezosetal,2009;.Macdonaldetal,2011;.Wakelinetal,2010a.),Andthereforemicrobialeffectsofheavymetalhasbecomeoneofthehotspotsofthecurrentinternationalresearch,includingheavymetalsmicrobialfunction(nitrification,denitrification,breathing,etc.)Communitystructureanddiversityoftheimpactonresearchdirectionsandthelike.Influenceofheavymetalsonspecificmicrobialcommunitywideconcern,suchasthenitrogencyclemicroorganisms.Liuetal.(2010)willaddadifferentmercuryTheconcentrationgradientofsoilwerecultured1,2,4,8weeks,measuringnitrificationpotential(PNR),wasfoundoneweeklater;withthemercuryconcentration,nitrificationpotentialdecreasedsignificantly,andeachconcentrationwassignificantlylowerthannitrificationpotential2,4,8weeks,Descriptionovertime,graduallyadaptedtothemicrobialoxidationofammoniamercurystressandonthefunctiongraduallyrestored;theabundanceandcommunitystructurefurtherresearchammoniaoxidizingbacteria(AOB)foundnosignificantdiffereneebetweenAOBabundanceineachtreatment,ButwiththeincreaseinmercuryconcentrationsincommunitycompositionAOBcluster3a.1percentagedecreasedsign讦icantlyhastenPotential,cluster3a.2betweentreatmentswerenotsignificant,cluster7existsonlyinthemercurycontaminatedsoil.ThisresultsinacertainextentexplainswhyPNRgradualrecovery,namelytheabundanceofAOBalthoughnotchangedsignificantly,butthecommunitystructurehasundergonesignificantchanges,mercuryresistaneeandtoleraneehasbecomethedominantspeciespopulationssothatAOB'sfunctiongraduallyrecovered・AndLiustudysimilar;Ruytersetc.(2010a)studyfoundthatsoilafter1to2yearsofzincpollutionnitrificationactivitygraduallyrecoveredandbygraduallychangingthecommunitystructureofheavymetalpollutionadaptabilitynitrifyingbacteriacommunitystructureofammoniaoxidizingbacteriaMain(Ruytersetal.,2010b).Fordenitrifyingmicrobeshavesimilarfindings,Holtan-Hartwig(2002)toaddcopper,cadmium,zincthreekindsofheavymetalsintothesoiltostudyitsimpactonthedenitrifyingmicrobialactivityfounddenitrificationactivityinthefirstdayssign讦icantlydecline,thefirsteightdaysbegantorecover,fullyrestoredtwomonthslater.Throughtheextractionofheavymetalsfromcontaminatedsoilcanbefoundinthecellsofmicroorganismshavebeenexposedtoheavymetalsproducedadaptabilityofbacteriaresultsalsoprovedthispointofview(Fern5ndez-Calvioetal.,2011).Inaddition,inresponsetoastudyofthedifferentinterfereneeanddisturbancessecondarytoreactivefunctionalstabilityofthesoilbycomparingsoilmicrobialecosystem・Tobor-Kaplonetal.(2006)usingbacterialgrowthratesandsoilrespirationtestend,throughresistaneeandresilieneeTocharacterizethefunctionalstabilityofthesoil.Testthesoiltowithstanddifferentlevelsofzincandcadmiumpollutionpollution,thisisthefirstinterferenee;andthensubjectedtothermalinterference,leadandsaltstress,thisisasecondaryinterference・Theresultsshowedthatadisturbsneeinthehighestdegreeofcontaminationofsoiltosaltstressandthermalstressresistaneeandresilieneethatisthelowest,whichconfirmsundergodramaSystemstrongabilitytowithstandexternaldisturbancesagainstresshypothesiswillbesign讦icantlydecreased,andthisabilitytorespondtoexternalstressandthedeclineisrelatedtotheintensityofthefirstdisturbanee.However,studieshaveshownthatoncethesystemhasactuallyincreasedinterfereneeAbilitytofightsecondaryinterferenee.Tobor-Kaplonetal.(2006)studyresultsalsoshowedthatbacterialgrowthrateamongthevariousprocessingexhibitdifferentlaws,thelowestdegreeofcontaminationofsoilsalinitystressonmaximumresistaneeandresilienee.\nIncontrast,thehighestlevelofsoilcontaminationonthethermalinterfereneeStresshighestresistaneeandresilience，thisresultisbranchedHoldahigherdegreeofstress,secondarystressresistaneeandresilieneeofthehigherhypothesis,becauseafterastresssystemtoobtaintheabilitytofightstress.Griffithsetal(2001)foundthathydrocarboncontaminatedsoilisnotcontaminatedplantscomparedtocontrolsoildecompositionrateofthesecondaryheatstressandcopperstressshowedhighresilienee.Philippotetal.(2008)alsofoundthatthesoilnitrate-reducingbacteriathroughacopperstressafterstresssecondarymercuryrecoveryweregreatlyenhanced.ThisissimilartofindingsMargesinetaL(2011),thatthesecondarystressfactorandastresscasethesamefactor,resistaneeandresilieneeenhancementofbacterialcommunities.Inthisstudy,theprimarystressinadditiontocopper;aswellasheattreatmentandherbicidetreatment,buttheheattreatmentandherbicidetreatmentofnitratereductionbacteriadidnotsignificantlychangethesecondaryHgstressresilienee.Basedontheaboveconclusions,themicrobialcommunitysecondarystressresponseAndamorecomplexrelationshipbetweenstress,stressresistaneeandtypeofresiliencesizeandstressfactors,inparticularthesecondstressfactorandastresstestthedegreeofsimilarityandtheendoftheselectionfactorshaveaverycloserelationship(Tobor-Kaplonetal.,2006),thetwoarelikelytoformsynergisticsimilarstresstoleranee(Philippotetal.z2008).Thereasonforthesedifferencesisthedifferentmicrobialcommunitiesdifferatdifferentstressresponsegenerated.Whilesomegroupsdisappeared,whileothersgroupsbecomedominantgroup,thesedominantgroupsrespondtoenvironmentalstressisthekey,dependingonthecharacteristicsofthedominantgroupsitselfsothatitproducesstressonspecifictolerance.3.2SoilmicrobialresponsetoenvironmentaistressquantitativedescriptionDuetosoilstabilityandsoilmicrobialecosystemhasacloserelationship,soinmanycasesneedtoquantitativelydescribethisrelationshipbetweenstabilityandenvironmentaldisturbances.Resistaneeandresiliencecanbecalculatedbythediffereneebeforeandaftertheagitationofthesamplecomparison.Atthissametimepayspecialattentiontothenodecomparestoeliminatethecontrolchangesinsoiloccursovertime,changesinfieldplotswiththeseasonschangeandthetrainingprocessoccurredinthelike,calculatedresistaneeandresilienceintheformslightlydifferent,summarizethespecificformulainTable1.Formformulaisdividedintoseveralcategories:①Considertheabsolutediffereneebetweenthesoil(Orwineta\,2004.);②theuseofsoildisturbancechangerelativetothecontrolsoil(Griffthsetalz2000;.Chaeretalz2009;.Sousaetalz1980;.Kaufmanetal1982);③synthesisofvariousmethods(Zhangetal,2010;.Oneilletal,1976)..Orwinetal(2004)suggestthatthereactionofmicrobialresistanceandresilieneeoftheformulamustmeetthefollowingconditions:CDTheformulamustbewiththeresistaneeorresilieneeincreasesmonotonically;②theformularequiredboundedpositiveandnegative,cannottendtoinfinity;Whenyoucannotbuildtheformula③denominatoriszero;④resistaneeshouldbestandardizedbytheundisturbedsoil(controlsoil),changesinthesizeoftheforcerequiredtorestoretheinitialdisturbancecausedbystandardization.4.EcologicalmechanismsofresponsesofsoilmicrobialcommunitytoenvironmentalstressesBiomesconstantlysubjectedtoavarietyofrandomlychangingevents,interfereneeisacommon\nphenomenoninnature.Somepeoplethinkthattobreakthestabilitybiomesinterference;however;themajorityofmodernecologistsbelievetheinterfereneeisameaningfulecologicalphenomena,itmakesthecommunitybythestatetobalancetheimbalanee,highlightingtheinterfereneeintheformationofcommunitystructureanddynamicsRole.Connellputforwardtheintermediatedisturbsneehypothesis(intermediatedisturbancehypothesis)(Rae,2000),thatamoderatelevelofinterfereneecanmaintainahighdiversity.Dengetal.(2011)foundthatMethaneoxidationactivitypyreneresilieneeonlywhenthelowerpyreneconcentration®thisprocessalsoincreasesthediversityofmethane-oxidizingbacteria.Highconcentrationsofpollutants,thediversitydecreasedsignificantlyandunrecoverable.Similarly,Wakelin(2010b)studiedthedifferentconcerttrationsofcoppercontaminatedsoilfoundthatchangesinmicrobialdiversitywasgraduallyreducedsinglepeakshapewhichistobeincreasedtothehighestpoints),whichisalsoconsistentwiththeintermediatedisturbancehypothesis.Microbialcellscanbetransferredviahorizontalgeneormobilegeneticfactortoobtainimmunity(Springaeletal.,2004),obtainedbyhorizontaigenetransferofexogenousgenesdegradingpollutantsledtomicrobialcommunitystructureanddiversitychanged,differenttheabilityofmicroorganismstoresistforeigninterferenceisdifferent,throughhorizontaigenetransfergeneratesmoreresistanceabilityofmicroorganismstoachieveadaptationtoexogenousdisturbances(Springaeletal,2004;.Ramosetal,2009;.Udikovic'-Kolic1etal.z2011).Microfloradisturbaneeresistaneeandresiliencesizebutalsowiththedegreeoffunctionalredundancycommunitychange.Thehigherthedegreeoffunctionalredundancy,thattherearemorespeciesperformingthesamefunction.Whenthebiologicaldiversityoftheseredundantcomponentscanbereducedasabuffertomaintainthenormalfunctionoftheecosystem.Wertzetal.(2007),non-sterilesoilsolutionbydilutionandtheninoculatedinsterilizedsoilwhichinturnformedthedifferentgradientsofmicrobialdiversity,microbialcommunitiesfoundindifferentexogenousheatstressresistanceandresilieneearedifferent,nitrificationmicroorganismsCompareddenitrifyingmicroorganismssusceptible,becausenitrificationdenitrifyingmicroorganismshighermicrobialdiversitycompareddenitrifyingmicroorganismsandthereforethedegreeoffunctionalredundancyandhighersothatthediversitydeclinehasbeenbuffered・4.1ResistantmicroorganismsandthelevelofresistaneegenetransferThereasonfortheheavymetalpollutionofsoilmicrobialcommunityresistanceandresilieneeinelude:①toleraneeinsteadoftheoriginalspeciessensitivespecies;②geneticvariationledtotheemergeneeofresistantspecies;③heavymetalresistaneegenetransferlevel;④Bioavailabilityofheavymetalslower.Ithasbeenreportedbetweenthegeneticlevelbydifferenttypesofbacteriainsoilplasmidtransferphenomena(Springaeletal.,2004),andwiththeheavymetalpollutionlevels,increasedfrequencyofhorizontaigenetransfer(Smallaetal.,2002).Someheavymetalssuchascopperandzinc,arecertainenzymesandelectrontransferChainessentialcofactorforcellfunctioninviewofheavymetalplaysanimportantrole,bacteriamustbeingestedasmallamountandtoxicityhaveacertaintolerance・Manystudieshavebeenreportedinthetranscriptionalregulationofthegeneproductofmicroorganismsonphysiologicaldisturbaneetoleraneeandadaptability(Ramosetal,2002;.Huismanetal,1996.)・Bacteriahasproducedavarietyofheavymetaladaptationmechanism,typicallytheplasmidtoleratedbyhorizontaigenetransferandthenextendedtotheentirebacterialcommunities(Coombsetal,2004;.Martinezetal,2006.),This,heavymetalalsoItbecameoneofthedrivingforcesofevolutionofmicrobialcommunities.Duetotheexistenceofhorizontalgenetransfereffect,microbialcommunitiesareusuallycomposedofmanyspeciescompositionofmetabolicinteractions,whichfortheresearchcommunityleveladaptationmechanismprovidesagoodmodel(Swensonetal.,2000).Intheory,anincreaseinplantcommun\nitiesmaybefunctionallysimilargenotypeInordertoincreasethelikelihoodoftheemergeneeofresistaneeinordertoreplacethedisappearsneeofspecies,orreducethenumberofspeciesresistanttostressorperturbation.Therefore,manystudieshavedemonstratedapositivecorrelationbetweenmicrobialdiversityandfunctionalstabilityof(MeCann,2000).ChangesanalysisHemmeetal.(2010)usingmetagenomicsstudiesofheavymetalpollutionofgroundwatermicrobialcommunitydiversity,thestudyfoundthatheavymetalpollutioncausedbymicrobialspeciesdiversityofgroundwater,bothallelicdiversityandmetabolicdiversityItdecreasedsignificantly,althoughviablemicrobialcommunityalsomeettheirsurvivalandgrowthofavarietyofmetabolicprocesses,butthestructureofthecommunitybecomesverysimple,heavymetalpollutionasastrongselectionpressuretobeabletoincreasetheirresistaneetothespecies,thustheformat!onofanewcommunitystructure・Amongthese,thelevelofresistaneegenetransfermaybethemainmicrobialcommunityadaptationtoenvironmentaistress.Inadditiontoheavymetals,studieshavedemonstratedthepreseneeofsoildegradationoforganiccontaminantsexogenousgenehorizontaltransfer(Springaeletal.,2004).Thesefindingsillustratethefulllevelduetothetransferofresistaneegenesandresistantmicroorganismsleadsanddiversityofsoilmicrobialcommunitystructurechanges,andthusmakesoilmicrobialcommunitiesResistaneetoenvironmentaistressandrestoringforceincreases・4.2soilmicrobialcommunityfunctionalredundancyFunctionalredundancyreferstocertainspeciesintheecologicalfunctionsofaconsiderabledegreeofoverlap,whichisremovedafteracertainspecies,ecosystemfunctionsshouldremainthesameorclosetothenormalstate(Wohletal.,2004).Ifmicrobialcommunitystructureafterbeingsubjectedtooutsideinterfereneemajorchangestookplace,theinternalmicrobialcommunityfunctionalredundancysufficienttomaintainthenormalfunctionofthewholecommunity-Manystudiesofthestabilityofthesoilfunctions(resistaneeandresilienee)areinterpretedassoilbiodiversityintrinsicfunctionalredundancy(Griffthsetal,2000,2004;.Chaeretalz2009.).Therefore,thestudyoffunctionalredundancyspeciesimportantroleplayedbythemechanismmaywellexplainthepotentialecosystemstability,andcanstudythepotentialvalueofspeciesdiversityonecosystemprocesses(Wohletal.,2004).Chaeretal(2009)comparedthefunctionalstabilityofvirginrainforestandcultivatedsoilmicrobialcommunities(resistanceandresilienee)size,theenzymeactivityasanindicatortothereaction.Beforeandafterheatshock,whetheritisvirginrainforestsoilorsoiltillage,broad-spectrumhydrolase(diacetateluciferase)activitywereseverelyaffected,thisresultconfirmsthesoilmicrobialcommunitieswithhighfunctionalredundancythisview•Girvanetal.(2005)alsoobtainedsimilarresults,theyfoundthatafteraddingbenzeneandcoppercontamination,broad-spectrumfunction(smallmaltdecomposition)contaminationbeforeandafterlittlechange,whilespecialFunction(DCPdecompositioncapability)significantlydecreased.Functionallyredundantinternalfunctionaldiversityofcommunityandbetweencommunitiescanenhaneecommunityresilienceagainstenvironmentaistresses,becausethefunctionofacommunitymaybelostordroppedbyotherfunctionallysimilartoacommunityorseveralcommunitiestoreplaceormakeup(Wardwelletal.,2008).Difficultiesnaturalmicrobialcommunitylinksbetweenmicrobialdiversityandfunctionhasbeenstudied,bothbecauseoffunctionalredundancyinmanycasesleadtonotshowedasignificantcorrelation.ResultsComteetal.(2010)intworespectsprovedthepresenceoffunctionalbacterialcommunityahighdegreeofredundancy:oneisthechangeintheamplitudeofthethird-orderforaspecificsiteofbacterialcommunitiesfunctionandbacterialcommunitystructureintheorderof\nmagnitudeoffourchangesinthedegreeofchangeisgreaterthanthepowerofcommunitystructureEnergy;thereisahighdegreeoffunctionalredundancybetweenmicrobialcommunitieswithintheregionalcontextontheotherhand,thatthereisasubstantialchangeincommunitystructureandfunctionisonlyaslightchange,theyarenotrelatedtrends.Didieretal.(2012)alsoobtainedasimilarconclusion,theyobservethesaltaroundthedisturbaneeplanktonicbacterialcommunitystructureandfunctionofthesimilarityfoundthatcommunitystructureofplanktonicbacteriabeforeandafterthedisturbaneechangesigrdficantly,howeverthecorrespondingfunctionwillonlyoccurminorThechanges,whichreducethemicrobialspeciesbutthefunctiondoesnotdecay,thusprovingtheimportantroleoffunctionallyredundant.Merceetal.(2012)alsofoundnoassociationbetweenbacterialcommunitystructureandfunctioninmostcases,youmayhavethefollowingthreereasons:①plasticity;②functionalredundancy;③responselag.Experimentalresultsshowthatthecarbonutilizationrateforthisfeature,itsnotanychangesandtheendoftheexperimentisconsistentwithundisturbedcontrolprocessbeforeandafterthedisturbanee,butbacterialcommunitystructurehasalreadychangedalot,andmicrofloraknotTherelationshipbetweenstructureandfunctionisdynamic,thetwoarenotdirectlyrelated.Alltheseresultswereindicativeoffunctionalredundancywidespreadmicrobialcommunitiesandmaintainnormalfunctionofthebacterialmicrofloraplaysacrucialrole.Microbialcommunityismoresensitivetoenvironmentaistressandingeneralcannotbequicklyrestoredtoitsoriginalstate,butchangesinmicrobialcommunitystructure,butdidnotaffectecosystemprocesses.Therearetwopossiblereasons:①newcommunitiescontainoriginalcommunityfunctionallyredundantunit.②eachfunctionalunitwithinthenewcommunitymayhaveonthecommunityfunctionofeachfunctionalunitwiththeoriginaldiffereneebutinthecommunityasawholedidnotaffectthelevelofthenormalcourseofecosystems(Allisonetal.,2008).4.30thermechanismsEnvironmentalstresscanalsoleadtotheoccurreneeofprokaryotesandeukaryotesproteinmisfoldingoraggregation,denaturationandaggregationofbacterialproteinsoccurunderheatstress.Heatshockproteinisinducedatahightemperaturetoproduceaproteinthatcontainsamolecularchaperoneproteincanpreventtheoccurreneeofaggregationofmisfoldedproteinsandtoassistrecovery,andcontainsanon-proteaseresponsiblefortheirreversibledamageofthepolypeptide(Libereketaldegradation..2008)」thasbeenconfirmedinE・colicells,heatshockproteincontentdecreasedproteinaggregationwillleadtothepossibilityoftheoccurreneeofelevated(Kedzierskaetal,1999;.Tomoyasuetal,2001.).5.0ProblemsandperspectivesOverall,soilmicrobialcommunitiesrespondtoenvironmentalstresshasmadesomeprogress,promotethestudyofsoilmicrobialresponsetoenvironmentalstressmechanismof.HowevecthekeyproblemplaguedsoilmicrobialresistaneeandresilieneequantitativedescriptionstillexistsonthesoilmicrobialcommunitystructureandfunctionaldiversityitselfmoreKindofdescriptionisstillverylacking,manyindicatorsusedtocharacterizethediversityofthecommunitystructureofthemacro-ecologyarenotwellusedinmicrobiologyfield.Thecurrentmethodsofmolecularbiologycannotestablishalinkbetweenmicrobialdiversitybasedongeneticindicatorsoffunctionalspec讦icationsbasedonmicrobialactivityanddiversity,andevenhowtodescribethefunctionaldiversityofmicroorganismsisalsostillunclear.Butitshouldbebetweenthetwoandthere\nisaninevitablelinkbetweentheresistaneeandresilieneeofsoilsystems.Furthermore,thereisbetweenmicrobialdiversityandstabilityofthesystemassociatedwithcertainsoilecology,andenvironmentalstressonsoilecosystemstability.Atpresent,thesetwoaspectsaremoremature,butthestudyoftherelationshipandtheirresponsestoenvironmentaistressbetweensoilmicrobialdiversityisstillveryscarce,thiswillbethenextfocusofthestudy.InMicrobialEcology,stilllacksaneffectivemodeltopredicttheimpactofenvironmentaistressmaybecausedbymicrobialcommunities,whichpredictecosystemresponsestoglobalchangehasveryimportsntsignificanee.Therefore,wealsoneedtocarryoutmorein-depthworkcomparetheimpactofenvironmentalstressonmicrobialcommunityindifferentandspecificfunctionsofmicrobialcommunities,whileexperimentallydeterminedresponsebycontrollingmicrobialphysiologicalindicators,tobuildapredictivemodelprovidesdatasupport.Onsoilmicroorganisms,weshouldcarryoutmoreIong-termfieldexperimentsinvestigatesoilbypositioningmonitorAftertheenvironmentalstressresponsemicroorganisms,soilqualitymonitoringandecologicalriskassessmentofsoilcontaminatedenvironmentstoprovidereliabletechnicalservicestoprovidedatatosupporttheestablishmentofsoilenvironmentalqualitystandards.Thishasimportantimplicationsfortheprotectionofsoilhealthandmaintainthestabilityofecosystems.Further,sincethemicroorganismsunderduresstoadapttothechangingenvironmentMutateandleadtoemergeneeofresistantspeciesofmicroflorainsidethegenetransferlevel,sothatthemicro-organismstoachieveanewstateofadaptation.Therefore,researchshoulddeepenantagonisticmicrobesandmicrobialcommunitiesinsidehorizontaigenetransfer;in-depthunderstandingofthemechanismofmicrobialresponsetoenvironmentaistress,andcanbeconsideredresistantmicroorganismsusedinpracticalsoilpollutioncontrol.Weexpectthatbystudyingsoilmicroorganismstoenvironmentalstress(mainlyforheavymetalpollution)inresponsetoacertainextentonthestabilityofthesoilecosystemcapableofreactingtoprovidecertainrefereneevaluefortheheavymetalcontaminatedsoilrestorationwork.References:AllisonSD,MartinyJBH・2008.Resistance,resilience,andredundancyinmicrobialcommunities[j]・ProceedingsoftheNationalAcademyofSciencesoftheUnitedStatesofAmerica,105:11512-11519BellT,NewmanJA,SilvermanBW,etal.2005.Thecontributionofspeciesrichnessandcompositiontobacterialservices[j]・Nature,436:1157-1160ChaerG,FernandesM,MyroldD,etal.2009・Comparativeresistaneeandresilieneeofsoilmicrobialcommunitiesandenzymeactivitiesinadjacentnativeforestandagriculturalsoils[j]・\nMicrobialEcology,58(2):414-424ChaoA,ChazdonRL,ColwellRK,etal.2005.Anewstatisticalapproachforassessingsimilarityofspeciescompositionwithincideneeandabundancedata[j]・EcologyLetters,8(2):148-159陈圣宾，欧阳志云，徐卫华，等.2010.Beta多样性研究进展[j]・生物多性，18(4):323-335ComteJ,delGiorgioPA.2010・Linkingthepatternsofchangeincompositionandfunctioninbacterioplanktonsuccessionsalongenvironmentalgradients[j]・Ecology,91(5):1466-1476ConditR,PitmanN,LeighEG,etal.2002.Beta-diversityintropicalforesttrees[j]・Science,295(5555):666-669CoombsJM,BarkayT・2004.Molecularevidencefortheevolutionofmetalhomeostasisgenesbylateralgenetransferinbacteriafromthedeepterrestrialsubsurface[J]・AppliedandEnvironmentalMicrobiology,70(3):1698-1707DangCK,ChauvetE,GessnerMO・2005.MagnitudeandvariabilityofprocessratesinfungalDiversitylitterdecompositionrelationships[J]・EcologyLetters,8(11):1129-1137DengHA,GuoGX,ZhuYG・2011.Pyreneeffectsonmethanotrophcommunityandmethaneoxidationrate,testedbydose-responseexperimentandresistaneeand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