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Photosynthesis-transpiration

By Jimmy Long,2014-02-18 17:15
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Photosynthesis-transpiration

    Photosynthesis-transpiration

    Photosynthesistranspirationcouplingmodelatcanopyscaleinterrestrial

    ecosVstem

    Ren,CYYu,GRWang,OFGuan,DX

    ChineseAcadSci,InstGeogSci&NatResourcesRes,Beijingl00l0l,PeoplesRChina ShenyangAgrUniv,Shenyangl10l6l,PeoplesRChina.

    ChineseAcadSci,lnstApplEcol,Shenyangl100l6,PeoplesRChina.

    ChineseAcadSci,GradSch,Beijingl00039,PeoplesRChina.

    Abstract:Atthehypothesisofbigleaf,anecosystemphotosynthesis

    transpirationcouplingcyclemodelwasestablished

    bythescaledSMPT-SBmodelfromsingleleaftocanopy,andmodelparameterizationmethodswerediscussed.Through

    simulatingthecanopylightdistribution,canopyinternalconductancetoCO2canbescaledfromsingleleaftocanopyby

    integratingtocanopyusingtherelationshipbetweensingleinternalconductanceandphotosyntheticphotonfluxdensity.

    UsingthedataobservedbyeddycovariancemethodfromtheChangbaiMountainssiteofChinaFLUX,theapplicationof

    themodelatthecanopyscalewasexamined.Undernowaterstress,thesimulatednetecosystemphotosynthesisratefitted

    withtheobserveddataverywell,theslopeandR-2ofthelineregressionequationoftheobservedandsimulatedvalues

    were0.7977and0.8892,respectively(n752),andaverageabsoluteerrorwas3.78mumolCO2m(2)s(1):theslope,R-2and

    averageabsoluteerroroftranspirationratewere0.7314,0.4355and1.60mmolH20m(

    2)s(1),respectively(n=752).The

    relationshipbetweencanopyphotosynthesis,transpirationandexternalenvironmentalcond

itionswasdiscussedbytreat

    ingthecanopyasawholeandneglectingthecomprehensivefeedbackmechanismwithincanopy,anditwasnotedthatthe

    precipitationcourseaffectedthetranspirationratesimulationbadly.Comparedtothemodelsbasedonecophysiological

    processes,theSMPT-SBmodelwassimpleandeasytobeused.Anditcanbeusedasabasiccarbonandwatercoupling

    modelofsoilplantatmospherecontinuum.

    Keywords:photosynthesisrate;transpirationrate;SMPT-SBmodel;internalconductance;canopyscale

    SCIENCEINCHINASERIESD-EARTHSCIENCES2005,48(Supp1.1):160171

    Apparentquantumyieldofphotosynthesisofwinterwheatandits

    responsetotemperatureandintercellularCO2concentrationunderlow

    atmosphericpressureonTibetanPlateau

    Shi,PLZhang,XZZhong,ZM

    ChineseAcadSci,InstGeogSci&NatResourcesRes,Beijing10010I,PeoplesRChina Abstract:TheTibetanPlateauischaracterizedbyloweratmosphericpressure,lowerairtemperatureandhighdailyand

    seasonalvariationduetohighelevation.Thephotosynthesisofplantsissignificantlyinfluencedbythesealpineenviron

    mentalfactors.Apparentquantumyield(alphaA)isoneofthebasicparametersofphotosynthesisandmassproduction.Its

    accuracydeterminationisofsignificancetomodelphotosynthesisOfC

    3plantsandglobalchangeontheplateauInthe

    LhasaPlateauEcologicalStationwith65.4kPaofatmosphericpressureatanelevationof3688m,UCor6400portable

    photosynthesissystemwasusedtomeasurelightresponsecurvesofwinterwheatindifferenttemperaturesandintercel

    lularCO2concentration(C).TheslopeoflightresponsecurveinweaklightareaofPFDfrom0t

o150mumolm(2)s(1)was

    usedtoevaluatethevalueofalpha(A).Thedependenceofalpha(A)ontemperatureandinterce

    llularconcentrationwas

    

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