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1、ID#32-09LENGTHANDWIDTHTOESTIMATEDRYMASSOFPANICUMMAXIMUMCV.TANZÂNIALEAVES1112L.G.Barioni,P.M.Santos,A.ColdebellaandM.Corsi1PhDstudent.DepartamentodeProduçãoAnimal,UniversidadedeSãoPaulo,Piracicaba,SP,2Brasil,13418-900,lgbarion@carpa.ciagri.usp.br.DepartamentodeProduçãoAnimal,UniversidadedeS
2、ãoPaulo,Piracicaba,SP,Brasil,13418-900AbstractAnanalysisoftherelationshipofleaflength(LL)andleafwidth(LW)withleafdryweight(LDW)inPanicummaximumwascarriedoutwiththeobjectiveofimprovingestimationsoftissueflowinthatplant.Datawascollectedinamobgrazingexperimentwith28daysgrazingintervalsampledt
3、hedaybeforegrazingin9grazingcycles.Regressionanalysisrevealedhighlysignificanteffect(P<0.001)ofbothLLandLWonLDW.Alackoffittestgavestrongevidencebofnon-linearrelationshipofLDWwithLL(p<0.05),fittingthemodelLDW=bLL1,while0LWpresentedalinearrelationwithLDW.LLwasabetterpredictorofLDWthanLW.LLso
4、lely2orincombinationwithLWproducedequationswithhighR(0.61–0.90and0.80–0.92,respectively).Thepowerrelationshipbetweenleaflengthandleafdryweightimplythatlongerleavesareheavierperunitoflengthand,thereforetheuseofaconstanttodescribedryweightmaybemisleadingwhentreatmentsaffectleafsizeinPanicumm
5、aximumpastures.Keywords:Leaf,model,weight,regression,PanicummaximumIntroductionLeafareaindexandleafmasshaveoftenbeenpointedoutasimportantstatevariablesinpastoralsystems,affectingonbothplantphotosyntheticpotential(HayandWalker,1989)andherbageintakebythegrazinganimals(Poppietal,1981;Floreset
6、al.,1993;ForbesandColleman,1993)andarethereforevaluableindicatorsofpasturestatus.Alsomethodologiesforquantifyingtissueflowrelyonmeasurementofleafelongationandlengthofsenescentpartofthetissue.Calculationsusuallyassumeconstantdryweightperunitoflength(usuallymm)inordertoestimatetissuemassflow
7、rates(Grantetal.,1983).Thispaperaimstoanalyzetherelationshipbetweensizemeasurements(lengthandwidth)andthedryweightofPanicummaximumcv.Tanzânialeavesinordertoimproveestimationsofleafmassandtissueflowinthoseplants.MaterialandMethodsDatawascollectedfromamobgrazing