INTRODUCTIONLowfertilityisthemostimportalssi ngleprobleminre--vegetationofbarrenlands(Po khriyaletal.,1987).Sincenitrogenisgenerally deficientinsuchlands,reforestationcanbesucc essfullyaccomplishedbyemployingselectedtree species,whichfixatmosphericnitrogen(Pokhriy aletal.,1987).Inoculationsofspecificmicroor ganismssuchasRhizo6iumspp.increasetreeprodu ctivity(SaxenaandTilak,1994)byimprovingthen itrogenfixationandavailabilityofotherminera ls.TheseRhizobiumfixesatmosphericnitrogenin therootnoduleoftreesbyestablishingasymbioti crelationship.InoculationofRhizo6iumhasnoil leffectsonsoilsystemsandhelpsboostthemicrob ialpopulationspreselltinthesoilwhichinturnm aketheinsolublenutrientsavailableforgrowtho ftheplants(Vermaetal.,1996).Manyscielltists haveemphasizedtheplaal-microbeinteractionan dtheimportancehasbeenrightlyplacedtostudyth eeffectofRhizo6iumontreeproductivity(Schrot handWeinhold,1986).Forlasttwodecades,severa lexperimentshavebeenconductedonbiofertilize randinoculanttechnologywithregardtotheireff ectongrowthoftreespeciesbutresearchesaresti llmeagre(Vermaetal.,1996).Tocontrolthealarm ingrateofdeforestationandtominimizefuelwood andtimberdeficit,exotictreeshavebeenplanted invastareas.However,duetoecologicalconstrai ntsofthesetrees,ithasbeensuggestedthatnativ eanddomesticatedtreespeciessuchasAlbizziapr ocero,Albizzialeb6eckandLeucaenaleucocephal ashouldbeintegratedinparticipatoryforestrys ystems.Thesespeciesandsuchothernitrogen-fix ingtreespeciescansuccessfullycolonizeinacid ic,salineanddrymarginallandspartlyduetothei nteractionbetweenthehostplantandtherootnodu lebacteria(Spread,1986,1995).Detailedresear chisnecessarytounderstandthebiologicalnitro genfixationinforestecosystems.First,thereis agreatneedtoelucidatethenodulationandnitrog en-fixingbehaviorsofthemostpromisingnativea nddomesticatedtreespeciesunderdifferentagro climaticconditions(Tewari,1998)andtoidentif ysuitablenitrogen-fixingtreespeciesnativeto thelocalityandthrivingwellwithpotentialsfor nitrogenenrichmentandameliorationofthesite( SinghandPokhriyal,1998).Inthepresentstudyan attempthasbeenmadetostudytheeffectofinocula tionofRhizo6iumsuspensiononthegrowth,nodula tionandbiomassproductivityofA.parcel.)A.leb beckandL.leucocephala.MATErnALSANDMETHODSTh epresentexperimentwasperformedinthenurseryo ftheinstituteofForestryandEnvironmentalScie nces,UniversityofChittagong,Bangladesh.Fort hisstudy,thesoilswereobtainedfromadepthof4- 10cmofthedegradedhillsoftheChittagongUniver sityCampus.TheaveragePHofthesoilis5.5(Badru ddinetal.,1989)withtextureofloamtosandyclay loam(Osmanatal.,1992).Theeffectivebrown/pin kcolorednodulesofA.proceru)A.lebbeckandL.le ucocephalawerecollectedfromthelateralrootso fhealthyandsuperiorseedlingsinthenursery.Th enodulesweresurfacesterilizedbyimmersinginm ercuricchloride(HgC12)solution(1gkg--')fort hreeminutes,thenintohydrogenperoxide(HZO2)s olution(300gkg--')for15minutes(Vincent,1970 ).Thesterilizednoduleswererinsedwithdistill edwaterseveraltimesandcrushedwiththehelpofs terilizedbladeandneedle.Theresultingsapsusp ensionofnodulebacteriawasculturedintheyeast extractmannitolagar(YEMA)medium(Vinceat,197 0)withPH7.Afterinoculation,thepetridisheswe reincubatedfor7days.Rhizobialstrainswerepur ifiedbyrepeatedsub-culturinginthesamemedium .Forgrowthstudiesofthebacteria(30"C)andprod uctionofRhizobiuminoculallt,thesamemediumwa susedwithoutagar.TheRhizo6iumdensityofthein oculantwas3x106cellspermLofsuspension.Hards eedswerescarifiedwithconcelltratedsulfurica cidfor30minutes.Otherseedsthatarenotveryhar dweresurface-sterilizedfirstbrieflywithdilu tedethanol(0.95m3m--')andthenwithacidifiedm ercuricchloride(2gkg--'in5mLHCI)for3-5minut es(Vincent,1970).After10timesofsubsequentwa sheswithsterilewater,seedsweresoakedinsteri lewaterovernightandtransferredtopolyethylen ebags(10cmx15cm)filledwithsterilizedornon-s terilizedsoil.Twoorthreeseedsweresownineach polyethylenebagandafter10dabsexcessseedling swereremovedandonlysinglehealthierseedlingwasretained.Thesoilsamplesweresterilizedinanautoclavefor20minutesat138kpaand121oC.Thetreatmentswerearrangedinrandomizedcompleteblo
More abstracts about the Effect of Rhizobium inoculation on Growth and Nodulationof Albizzia procera, Albizzia lebbeck and Le