简介：Potexperimentsandfieldtrialswereconductedtoinvestigatethechangesintrichloroaceticacid(TCA)solublesilicon(Si)intheleavesofrice(OryzasativaL.)andtoexaminethefeasibilityofusingTCA-solubleSicontentasanindexfordiagnosingSideficiency,TheTCA-solubleSicontentwassignificantlyhigherintheleavesofbothSi-treatedand-untreatedriceattheelongationstagecomparedwiththatattilleringstage,ItwashigherintheSi-treatedplantsthaninthecontrolsthroughoutthewholegrowthperiod.However,whetherdressedatelongationorbootinstage,siliconfertilzerresultedinasignificantincreaseinTCA-solubleSioneweektotendaysafterapplication,ThesamewastrueforthetotalSiaccumulationintheplants.AcolsepositiviecorrelationwafoundbetweenTCA-solubleSiandtotalSiinPlantsgrownonpotsoils(r=0.669,P<0.01,n=26).TheresultsobtainedinthefieldtrialsrevealedthattheavailableSiextrctedbysodiumacetate(pH4.0)couldnotpreicttheresponseofricetoaddedSiinthecalcareoussoilssatisfactorily.NosignificancorrelationwasfoundbetweensoilavailableSicontentandriceyield,butTCA-solubleSiintheleafbladesofricewassignificantlycoorelatedbothwithriceyield(r=0.57,P<0.01,n=30)andwithtotalplantSi(r=089,P<0.01,n=30),Inisrecommendedthat,whth95percentconfidence,thecriticalvalueofTCA-solubleSiintheleavesofriceshouldbe52-57mgSikg^-1,abovewhichnopositiveresponseofricetoaddedSiwouldbeexpected.