Seed tretment

SeedTreatmentQuestions:Whatisdormancy?Whatmethodsofseedtreatmentcanbeusedtoovercomeseedcoatdormancy?Whatismeansofstratification?Whatwilleffectsontheseedamangstratification?Specializedwordsandterms:imbibition：种子吸涨radicle：胚根dormancy：休眠endogenous：内源的seedcoat：种皮scarification：种皮损伤Leguminous:豆科Acacia：合欢属Albizia：金合欢属mesquite：牧豆树honeylocust:美国皂荚locust：豆科落叶乔木basswood：阔叶Blacklocust：刺槐ceanothus:美洲茶属stratification:层积处理incubation：培养juniper：刺柏属Ingeneral,seedsimbibewaterrapidlyatfirst,thenreachaplateau(lagphase)wherewateruptakeisverysloworstops.Thelengthofthelagphasediffersgreatlybetweenspeci-es.Dor-mantseeds,wheremoistureuptakeisnotlimitedbya'hard'seedcoat,tendtore-maininthisphaseuntildormancyisbrokenbytreatment.Growthoftheembryonicroot(radicle)istheninitiatedandwateristakenupagainastheradicleemergesfromtheseedcoatatgermination.Ingeneral,seedsimbibewaterrapidlyatfirst,thenreachaplateau(lagphase)wherewateruptakeisverysloworstops..KaywordsandScentencepoints:Imbibe:drink;takeinimbibeidea/knowledgeimbibition:themechanismofintialwateruptakebyseeds.thetakingupoffluidbyacolloidalsystem.～-nalwater,～-nalpressureplateau:originalmeaning:高原高地specialmeaning:平台；鳞茎盘～phaselagphase:Inconnectionwithgermination,thephaseafterimbibitionandbeforeradicleenlongatin.duringthelagphasethereisnoorverylittlewaterabsorpingandnoorverylittlesignofdevopmentLag:1.walktooslow,notkeepupwithThelameboylaggedbehind2.犯人：oldlag(惯犯)3.防水防散热材料：Topreventfreezingofwaterinpipes,wastingofheatLager:lightbeerGrowthoftheembryonicroot(radicle)istheninitiatedandwateristakenupagainastheradicleemergesfromtheseedcoatatgermination.KaywordsandScentencepoints:embryonic:胚胎的、胚的Embryo:胚（胎）embroytransfer(ET):胚移植；embryobud;～culturetechnology;～engineeing;～stemcell;Embryoid:胚状体embryology;embryologistradicle:Theembryonicroot,i.e.thepartoftheseedembryothatdevelopsintotheprimaryroot.Radicular（胚根的）;radiclting（生根的）Germination=germintioSprouting:萌发，发芽～pore;～capacity;～inhibition;extendedmeaning:1.germ-胚：germplasm;germplasmbank;germplasmresource;germplasmstorage;germplasmcollection2.germ：菌，微生物Germfreeplant;germicide(-dal)Therearetwoimportantpointsforthetreatmentandmaintenanceofseedperformance.•Asmoisturecontentincreases,therateofseeddeteriorationincreasesuntiltheseedbecomessufficientlymoistthatprocessesbegintooperatewhichenabletheseedtorepairtheaccumulatingdamage.Fortreatmentandmoiststorage,itisthereforebesttokeeptheseedatthemoisturecontentofthelag-phase.deterioration:worseinqualityaccumulating:becomegreaterinnumberorquantity:Byworkinghardyoucanaccumulateafortuneaccumlation(蓄电池)Aftertheinitiationofgermination,whentheradiclebeginstogrow,theseedsprogressivelylosedesiccation-toleranceandthustheopportu-nitytoredrytheseedsaftertreatrmentislost.WhatisDormancy?Seeddormancyisnature'swayofsettingatimeclockthatallowsseedstoinitiategerminationwhenconditionsarenormallyfavorableforgerminationandsurvivaloftheseedlings.Intiation:atthebeginning:intiationcodon;intiationsignal;intiationfactor;intiationsiteintial:原始的，起初的，首字母:Theintialletterofaword;theintialstagesofanundertaking(cause;career)Intiate:着手计划，开始Initiative：firststepormove(起步阶段):Peaceinitiative;taketheinitiativeDesiccation-tolerance(干燥耐受)becomegreaterinnumberorquantitydesiccant(干燥剂)；disiccate(干燥贮存);desiccatedfruitViableseedsthatdonotgerminatearesaidtobedormant.Whendormant,thereisablocktothenorlmalprogressofgerminationtoradicleemer-gence.Dormancycanberegulatedbytheenviron-mentorbytheseeditself.Ifaseedisnotexposedtosufficientmoisture,propertemperature,oxygen,andforsomespecieslight,theseedwillnotgerm-inate.Inthiscase,theseed'sdorm-ancyisduetounfavorableenvironmentalcond-itions.Ontheotherhand,someseedsmaynotgerminatebecauseofsomeinhibitoryfactoroftheseeditself.Thisparticularkindofdormancyconsistsoftwogeneraltypes:seedcoatorexternaldormancy;internal(endogenous)dormancy.Viableseedsthatdonotgerminatearesaidtobedormant.Viable:abletoexit,capableofdevelopingandsurvivingViability(生活力，生存力)endogenous:Originatedwithin,ordevelopedfromadeep-layeroftissue.Inaseed,developedfromoroccurringintheembryo.:endogenousgene;endogenousrhythm;endo-:内在的:endocrine;endocrinologyexogenous(外源的，外生的)exo-:外在的:exon(extron);exocuticula(外表皮)Therearesomespecies,includingmostconi-fers,whichareconditionallydormant.Theywillgerminatecomparativelyslowlyunderoptimalconditions,butnotatallundersuboptimalconditions.However,low-temperaturemoistpretreatmentimprovestheirperformancepart-icularlyundersuboptimalconditions.Thisisimportantbecausesowingisrecommendedwhenthesoiltemperaturerisestoaround10℃inspring,wellbelowtheoptimumtemperatureforgermination,whichformanyspeciesisabout20~25℃.Beforegerminationcantakeplaceinfullydormantseedstheymustundergophysicaland/orphysiologicalchanges.Aftershedding,undernaturalconditions,seedsintimebecomeexposedtothenecessaryenvironmentalstimulithatinducethechangesthatbreakdormancy.However,thishappensinanuncontrolledwayandthereforegerminationcanoccuroverweeks,monthsorevenyears.Effectivetreatmentsthatprovidesuchconditionsinacontrolledwaygreatlyred