论文Photosynthesis respiration and carbon allocation ofson .pdf

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1、PlantandSoil227:17–26,2000.17©2000KluwerAcademicPublishers.PrintedintheNetherlands.Photosynthesis,respiration,andcarbonallocationoftwocool-seasonperennialgrassesinresponsetosurfacesoildryingBingruHuang&JinminFuDepartmentofHorticulture,ForestryandRecreationResources,KansasStateUniversity,Manhattan,K

2、S66506,USAReceived22December1999.Acceptedinrevisedform31May2000Keywords:photosynthesis,rootrespiration,carbonallocationAbstractThestudywasconductedtoinvestigatecarbonmetabolicresponsestosurfacesoildryingforcool-seasongrasses.Kentuckybluegrass(PoapratensisL.)andtallfescue(FestucaarundinaceaeSchreb.)w

3、eregrowninagreenhouseinsplittubesconsistingoftwosections.Plantsweresubjectedtothreesoilmoistureregimes:(1)well-wateredcontrol;(2)dryingofupper20-cmsoil(upperdrying);and(3)dryingofwhole40-cmsoilprofile(fulldrying).Upperdryingfor30dhadnodramaticeffectsonleafwaterpotential(9leaf)andcanopyphotosyntheticr

4、ate(Pn)ineithergrassspeciescomparedtothewell-wateredcontrol,butitreducedcanopyrespirationrate(Rcanopy)androotrespirationrateinthetop20cmofsoil(Rtop).Forbothspeciesinthelower20cmofwetsoil,rootrespirationrates(Rbottom)weresimilartothecontrollevels,andcarbonallocationtorootsincreasedwiththeuppersoildry

5、ing,particularlyfortallfescue.Theproportionofrootsdecreasedinthe0-20cmdryingsoil,butincreasedinthelower20cmwetsoilforbothgrassspecies;theincreasewasgreaterfortallfescue.The9leaf,Pn,Rcanopy,Rtop,Rbottom,andcarbonallocationtorootsinbothsoillayerswereallsignificantlyhigherforupperdriedplantsthanforfully

6、driedplantsofbothgrassspecies.ThereductionsinRcanopyandRtopinsurfacedryingsoilandincreasesinrootrespirationandcarbonallocationtorootsinlowerwetsoilcouldhelpthesegrassescopewithsurface-soildroughtstress.Abbreviations:9leaf–leafwaterpotential;Pn–netcanopyphotosyntheticrate;Rtop–respirationrateofrootsi

7、nthetop20-cmsoil;Rbottom–respirationrateofrootsinthebottom20-cmsoil;TNC–totalnonstructuralcarbohydrateIntroductionPlantswithawell-establishedrootsystemcanutilizelocalizedsuppliesofavailablesoilwaterto