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1、SoilBiology&Biochemistry37(2005)179181www.elsevier.com/locate/soilbioShortcommunicationPlantcaptureoffreeaminoacidsismaximizedunderhighsoilaminoacidconcentrationsDavidL.Jonesa,*,DavidShannonb,ThippayaJunvee-Fortunea,JohnF.FarrarcaSchoolofAgriculturalandFores
2、tSciences,UniversityofWales,Bangor,GwyneddLL572UW,Wales,UKbSchoolofBiologicalSciences,DisciplineofPlantandSoilScience,UniversityofAberdeen,AB243UU,Scotland,UKcSchoolofBiologicalSciences,UniversityofWales,Bangor,GwyneddLL572UW,Wales,UKReceived23January2004;re
3、ceivedinrevisedform28May2004;accepted21July2004AbstractFreeaminoacids(AAs)representasignificantsourceofavailableNforsomeplantsandsoilmicroorganisms.Itcanbeexpected,however,thatsignificantcompetitionwillexistbetweenplantsandmicroorganismsforthisorganicNresource
4、.Ourstudyindicatedthatmicrobialcaptureandutilizationofglycinewasveryrapidatarangeofsoilsolutionconcentrations(0.1mMto10mM)indicatingthatsignificantcompetitionwillexistbetweenrootsandsoilmicroorganisms.PlantcaptureoffreeAAswasmaximalathighsoilsolutionconcentra
5、tionswheremicrobialutilizationwasslowest.OurresultssuggestthatplantcaptureofsoildissolvedorganicNmayprimarilyoccurinorganicrichpatchesinsoilwhereconcentrationsoffreeAAsarehigh.q2004ElsevierLtd.Allrightsreserved.Keywords:Aminoacids;Dissolvedorganicnitrogen;Gl
6、ycine;Mineralization;Nitrogenuptake;Rhizosphere;SoilsolutionDissolvedorganicnitrogen(DON)hasbeenshowntohighconcentrationsoforganicNwillexistatleastrepresentasignificantpoolofsolubleNinbothsoilsandtransientlyinsoil.Ouraimwasthereforetodeterminefreshwaters(Siem
7、ensandKaupenjohann,2002;Yu,2002).whetherthecompetitiveabilityofplantrootstocapturefreeInparticular,thedirectrootuptakeoffreeaminoacidsAAsfromsoilwasregulatedbyexternalconcentration.(AAs)fromsoilmaybeamechanismofcapturingNSoil(EutricCambisol)wascollectedfromt
8、heAhreleasedfromSOM,effectivelyshortcircuitingthereliancehorizon(015cm)ofafertilisedfreelydraininggrasslandofthemicrobialcommunitytocreateinorganicN(Nasho¨lm(LoliumperenneL.andTrifoliumrepensL.)
