简介:Nitratereductaseactivity(NRA)indifferentplantorgansandleavesindifferentpositionsofCamptothecaacuminataseedlingswasdeterminedbyanInvivoassay,thediurnalvariationrhythmofNRAinleavesofdifferentpositionswasobserved,andthecorrelationsbetweenleafNRA,leafareaandlaminamassperunitarea(LMA)werealsoexamined.TheresultsshowedthatNRAintheleafwassignificantlyhighest,comparedwiththatinotherorganssuchasroots,stemsandleaves.Inthisexperiment,the10leaveswereselectedfromtheapextothebaseoftheseedlingsinorder.ThedifferentNRAoccurredobviouslyinleavesofdifferentpositionsofC.acuminataseedlingsfromtheapextothebase,andNRAwashigherinthe4th-6thleaves.ThediurnalchangerhythmofleafNRAshowedaonepeakcurve,andmaximumNRAvalueappearedataboutmidday(at12:30orso).NoobviouscorrelationsbetweenNRAandleafareaorlaminamassperunitareawereobserved.ThisstudyofferedscientificfoundationforthefurtherresearchonnitrogenmetabolismofC.acuminata.
简介:Toxin,oneofthemostimportantfactorsofplantfungaldisease,hasattractedmuchattentionofmanyacademicianswhohavebeenstudyingpathogenmycotoxinindeepresearch.Thepapersummarizedchemicalstructuresofsomehost-selectiveplantpathogenmycotoxinsdiscoveredinrecentyearsandthecorrelationbetweenbiologicalactivityandchemicalstructureoftoxin.
简介:ThehumidagroclimaticconditionsofKerala,IndiapermitthecultivationofanarrayofbamboospeciesofwhichDendrocalamusstrictusRoxb.(Nees.)isanimportantoneonaccountofitshighgrowthrateandmultipleuses.Standdensity,apotentialtoolincontrollingtheproductivityofwoodyecosystems,itseffectongrowthandrootdistributionpatternsmayprovideabetterunderstandingofproductivityoptimizationespeciallywhenbamboo-basedintercroppingoptionsareconsidered.Growthattributesof7-year-oldbamboo(D.strictus)standsmanagedatvariablespacing(494m,696m,898m,10910m,12912m)werestudied.Functionalrootactivityamongbambooclumpswerealsostudiedusingaradiotracersoilinjectionmethodinwhichtheradioisotope32Pwasappliedtosoilatvaryingdepthsandlateraldistancesfromtheclump.Resultsindicatethatspacingexertsaprofoundinfluenceongrowthofbamboo.Widelyspacedbambooexhibitedhigherclumpdiametersandcrownwidthswhileclumpheightswerebetterundercloserspacing.Clumpheightwas30%lowerandDBH52%higheratthewidestspacing(12912m)comparedtotheclosestspacing(494m).Withincreasingsoildepthandlateraldistance,rootactivitydecreasedsignificantly.Rootactivityneartheclumpbasewashighest(809countsperminute,cpm;50cmdepthand50cmlateraldistance)at494m.Tracerstudyfurthershowedwiderdistributionofrootactivitywithincreaseinclumpspacing.Itmaybeconcludedthattheintensiveforagingzoneofbambooiswithina50-cmradiusaroundtheclumpirrespectiveofspacing.N,PandKcontentintheupper20cmwas2197,21,and203kg/harespectivelyforthecloselyspacedbamboo(494m)whichweresignificantlyhigherthancorrespondingnutrientcontentatwiderspacings.About50%ofN,PandKwerepresentwithinthe0-20cmsoillayer,whichdecreaseddrasticallybeyondthe20cmdepth.Theresultssuggestthatstandmanagementpracticesthroughplantingdensityregulationcanmodifyt
简介:更好在土壤上理解森林继任的效果微生物引起的活动,土壤的比较微生物引起的性质和营养素在代表自然森林继任chronosequence的三种森林类型之间被进行。学习比较了松(Pinusmassoniana)森林(P松和阔叶烟草混合了的F),森林(MF)并且一常绿树阔叶烟草森林(BYingzuijie生物圈储备地的F),,湖南省,中国。结果显示出那土壤在MF和BF阴谋比在PF阴谋。在微生物引起的生物资源碳的范围与B有最大的价值的F,5221022?mg?kg1,由MF368569?mg?kg1,并且最后,PF193449?mg?kg1。土壤营养素更强烈比基础呼吸或新陈代谢的商与微生物引起的生物资源碳被相关。总的来说,在学习地点的森林继任改善了玷污微生物引起的性质并且玷污富饶,它能接着增加主要生产率和碳隐遁。
简介:ThetaigaconiferousforestsoftheSiberianregionarethemaincarbonsinksintheforestecosystems.Quantitatively,thesizeofthecarbonaccumulationisdeterminedbythephotosyntheticproductivity,whichisstronglyinfluencedbyenvironmentalfactors.Asaresult,anassessmentoftherelationshipbetweenenvironmentalfactorsandphotosyntheticproductivitymakesitpossibletocalculateandevenpredictcarbonsinksinconiferousforestsattheregionallevel.However,atvariousstagesofthevegetativeperiod,theforceoftheconnectionbetweenenvironmentalconditionsandtheproductivityofphotosynthesismaychange.Inthisresearch,correlationsbetweenthephotosyntheticactivityofScotspine(PinussylvestrisL.)withtheenvironmentalconditionswerecomparedinspringandinautumn.Inspring,closepositivecorrelationofthemaximumdailynetphotosynthesiswasidentifiedwithonlyoneenvironmentalfactor.Fordifferentyears,correlationswereforsoiltemperature(rs=0.655,p=0.00315)oravailablesoilwatersupply(rs=0.892,p=0.0068).Inautumnwithindifferentyears,significantcorrelationwasshownwithtwo(temperatureofairandsoil;rs=0.789and0.896,p=0.00045and0.000006,respectively)andfourfactors:temperatureofair(rs=0.749,p=0.00129)andsoil(rs=0.84,p=0.00000),availablesoilwatersupply(rs=0.846,p=0.00013)andirradiance(rs=0.826,p=0.000001).Photosyntheticactivityhasaweakerconnectionwithchangesinenvironmentalfactorsinthespring,ascomparedtoautumn.Thisisexplainedbythemultidirectionalinfluenceofenvironmentalconditionsonphotosynthesisinthisperiodandbythenecessityofearlierphotosynthesisonset,despitetheunfavorableconditions.Thisdatamaybeusefulforpredictingtheflowofcarbonindependenceonenvironmentalfactorsinthisregioninspringandinautumn.