response of photosynthetic plasticity of paeonia suffruticosa to changed light environmentsnew

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1、EnvironmentalandExperimentalBotany49(2003)121
/133www.elsevier.com/locate/envexpbotResponseofphotosyntheticplasticityofPaeoniasuffruticosatochangedlightenvironments,1ShourenZhang*,KepingMa,LingzhiChenLaboratoryofQuantitativeVegetationEcology,CenterforPlantEcologyandBiodiversityConservation,Insti

2、tuteofBotany,TheChineseAcademyofSciences,Beijing100093,PeoplesRepublicofChinaReceived20July2001;receivedinrevisedform20August2002;accepted20August2002AbstractTemporalchangesingasexchangeandchlorophyllfluorescenceofPaeoniasuffruticosaseedlingsacclimatedtothreelevelsoflightenvironmentswereinvestig

3、ated.Therewasasignificantphotosyntheticdepressioninseedlingsacclimatedtoalongtimeofshadingandthensuddenlyexposedtofullambientradiation.Thedecreasedtranspiration(E)resultedfromfeed-forwardeffectmechanism[Aust.J.PlantPhysiol.5(1978)787].Anobviousphotosyntheticplasticitywasfoundwhentheseedlingswere

4、acclimatedtorespectivelightregimesfor1month.Thephotosyntheticrate(Pn)forseedlingsacclimatedtohigh-lightregimewassignificantlyhigherthanthatforseedlingsacclimatedtointermediate-andlow-lightregimes.ThedecreasedPnforseedlingsacclimatedtolow-lightregimewasattributedtonon-stomatallimitationwhenexpose

5、dtofullambientlight.AsignificantdecreaseinFv/Fmfortheseedlingsacclimatedtolow-lightregimeindicatedthatthephotosystemII(PSII)wasinactivatedwhenseedlingswereexposedtofullambientlight.Nevertheless,thephotosyntheticplasticityoftheP.suffruticosaseedlingswaslimitedtemporally.Alongtime(2months)ofhigh-l

6、ightexposuremaydamagethephotosyntheticapparatus.ThePnforseedlingsacclimatedtointermediate-lightregimewassignificantlygreaterthanthatforseedlingsacclimatedtohigh-andlow-lightregimes.#2002ElsevierScienceB.V.Allrightsreserved.Keywords:Acclimation;Chlorophyllfluorescence;Gasexchange;Shade1.Introducti

7、ontheticphotonfluxdensity(PPFD)variestempo-rally(seasonallyanddiurnally)andspatially,Lightisanimportantresourceforphotoauto-whichchallengeplantstodevelopacclimationtrophichigherplantsinsurvival,growthandandplasticitymechanis