简介：Basedonthestrongchelatingpropertyofbathophenanthrolinedisulfonicacid(BPDS)withFe(Ⅱ),rootFe(Ⅲ)chelatereductaseactivityisusuallymeasuredwithaspectrophotometerusingMES(2-morpholinoethanesulfonicacid)orHEPES(2-(4-(2-Hydroxyethyl)-1-piperazinyl)ethanesulfonicacid)bufferinthedarkbecauseofhighautoreductionrateofFe(Ⅲ)inthepresenceoflight.However,theexclusionoflightisinconvenient,especiallywhenanalyzingalargenumberofsamples.TheobjectiveofthisstudywastodevelopanewmethodfordeterminationofrootreductaseactivityundernormallaboratoryconditionsusingasuitablebuffercompositionandFe(Ⅲ)concentrationtoeliminatetheautoreductionofFe(Ⅲ).AmodifiedmethodusingaTris(2-amino-2-hydroxymethyl-1,3-propanediol)bufferatpH7.5insteadofMESorHEPESbufferandadecreasedFeEDTA(Feethylenediaminetetraaceticacid)concentrationof50μmolL-1wasdeveloped.TheautoreductionofFe(Ⅲ)usingtheTrisbufferwasundetectablefortemperaturesat4and28℃andwasalsomuchlowerthanthatusingtheotherbuffersevenwithsunlightduringmeasurementofFe(Ⅲ)reduction.Furthermore,thedifferencesinFe(Ⅲ)reductaseactivityamong5plantspeciesand14redclovercultivars(TrifoliumpratenseL.)couldbeeasilydetectedwiththemodifiedmethod.ThemethoddevelopedinthisstudytomeasurerootFechelatereductaseactivitywasnotonlyeffectiveandreliablebutalsoeasilymanagedundernormallaboratorylightconditions.

简介：Bothofstraightandincliningpoplarclone107treewereselectedforstudyingmaterialsinthispaper.Theoptimalpulpingconditionswasestablishedbyorthogonalexperimentaldesignbothfornormalwoodandtensionwood,andthequalityofpulpingandpaper-makingbetweennormalwoodandtensionwoodwascomparedwitheachother.Finally,potentialapplicationforimprovingpaperqualityoftensionwoodthroughincreasingbeatingrevolutionswasdiscussed.Theresultshowedthattheoptimalcookingconditionfornormalwoodwasalkaliconcentration15%,thehighesttemperature164℃,timeathighesttemperature75min,andfortensionwooditwasalkaliconcentration13%,thehighesttemperature160℃,timeathighesttemperature40min.Pathcoefficientofeffectofalkaliconcentrationbothonpulpyieldandkappavaluewassignificantatdifferentlevels.Bycomparisonbetweenaverageresultofnormalwoodandtensionwoodinqualityofpulpingandpaper-making,itwasfoundthattensionwoodhadhigherpulpingyieldandlowerkappavaluethannormalwood.Furthermore,forallmechanicalpropertiesofpaper,normalwoodholdhighervaluethantensionwood,andevenneartwotimesthantensionwood,suchasburstindexandtensileindex.However,differenceoftearindexwasquitenarrow.ResultofonewayANOVAshowedthatdifferenceofburstindexandtearindexbetweennormalwoodandtensionwoodwassignificantatthe0.001level,oftearindexwassignificantatthe0.05level.Basedonobservationofcrosssurfaceofpaper,itwasassumedthatcontributionofgelatinouslayertorigidityofsinglefiberhadhamperedcollapseandcompressionoffiberduringpaperformation,whichisessentialforexertingcombinationbetweenfibersinpaper.So,mechanicalpropertiesoftensionwoodpaperweredecreasedaccordingly.However,owingtohighcellulosecontentofgelatinouslayer,tensionwoodwaseasiertopulpingthannormalwood.Mechanicalpropertiesoftensionwoodpapercouldbeimprovedbyincreasingbeatingrevolutions,