第二章藠头愈伤组织诱导的研究

第一章文献综述Chapter1:LiteratureReview藠头（AlliumchinensisG.Don），英文名rakkyo，又名薤头、荞头、火葱、野韭等，属百合科（Liliaceae）葱属（Allium）形成小鳞茎的多年生宿根草本植物，主要食用嫩叶和鳞茎,系中国南方特有的稀缺蔬菜品种之一，属辛香类蔬菜。藠头的叶片绿色、细长、中空，有大葱样辛辣气味，叶鞘基部膨大形成长卵或纺锤形鳞茎。藠头作二年生栽培，分蘖力强。其鳞茎的加工产品质地洁白，口感脆嫩，具防暑、开胃、助消化等保健功效。盐渍、甜酸藠头深受消费者欢迎，并出口东南亚及日本、韩国等国（文惠玲等，2003）。在中医中，藠头的干燥鳞茎又称为薤白（祝之友，2000），其味辛、苦，性温，无毒，具有宽胸、理气等功效，用于治疗胸闷刺痛、肺气喘急等疾病已有2000多年的历史。现代医学研究发现，薤白还具有抑菌消炎、解痉平喘、抗血小板凝聚、抗氧化、抗肿瘤、降低血脂、抗动脉粥样硬化的作用（张卿等，2003）。藠头既可食用又能入药，具有多种药理作用和保健的功能，是复合型功能食品，被誉为“菜中灵芝”。AlliumchinensisG.Don,withtheEnglishnameofrakkyo,isalsoknownasalliumbakeri,scallion,shallotandalliumramosum.ItbelongstothecategoryofAlliumgenusofLiliaceaefamily,andisakindofperennialherbwithcloves.Themainpartsofthisplantforfoodareleavesandbulbs.ItisoneoftheuniquescarcevegetablevarietiesinSouthChina,anditisclassifiedasspicyvegetable.TheleavesofAlliumchinensisG.Donaregreen-colored,slenderandcannular.IthasspicyodorlikethatofagreenChineseonion.Theleafsheathbaseenlargessoastoformlongovoidorspindle-shapedbulb.Itisbienniallycultivated,andhasastrongtilleringcapacity.Theprocessingproductsofitsbulbsarewhiteintextureandcrispandtenderintaste,havinghealthcareeffectssuchassunstrokeprevention,appetitepromotion,anddigestionaid.Saltedandsweet&sourAlliumchinensisG.Donproductsarewellreceivedbycustomers,andareexportedtoSouthAsia,Japan,SouthKorea,etc.(WenHuiling,2003).IntraditionalChinesemedicine,thedrybulbofAlliumchinensisG.Donisalsocalledalliummacrostemon(ZhuZhiyou,2000)withpungentandbittertaste,andwildnature,whichisfreefromtoxicity.Ithasthefunctionssuchascomfortingthechestandregulatingtheflowofvitalenergy.Ithasbeenusedinthetreatmentofdiseaseslikechesttightnessandtwinge,lungdyspneaformorethan2000years.Accordingtothefindingsofmodernmedicalresearch,alliummacrostemonisalsocapableofinhibitingbacteria,eliminatinginflammation,relievingspasm,calmingbreathing,resistingplateletaggregation,oxidationandtumors,reducingbloodfat,andfightingatherosclerosis(ZhangQing,etal..).AlliumchinensisG.Donisnotonlyediblebutalsocapableofbeingtakenformedicinepurpose.Ithasmultiplepharmacologicaleffectsandhealthcarefunctions,andisakindofcompoundfunctionalfood.Therefore,itishailedas“ganodermalucidumofvegetables”.藠头原产于我国，已有3700多年的种植历史，先秦时已广为利用。以江西、湖南、湖北、广西、云南、四川、贵州等省（区）栽培较多，目前在江西新建、云南开远以及武汉江夏梁子湖等地区有大面积植。在浙江和西藏还有野生种群（陈静芬，1989）。俄罗斯、朝鲜、日本都有分布和少量栽培（柳荣成，1995）。AlliumchinensisG.DonisoriginatedfromChina,andhasaplantinghistoryover3700years.ItwaswidelyusedasearlyasPre-QinDynasty.IthasbeenmostlyplantedinJiangxi,Hunan,Hubei,Guangxi,Yunnan,SichuanandGuizhou.Currently,itisplantedwithlargeareasinregionssuchasXinjianinJiangxi,KaiyuaninYunnan,andJiangxiaLiangziLakeinWuhan.Also,therearewildpopulationinZhejiangandXizang(ChenJingfen,1989).AlliumchinensisG.DonisalsodistributedinRussia,NorthKoreaandJapanwithlimitedplantingquantity(LiuRongcheng,1995).藠头栽培种多为三倍体、四倍体等多倍性植株（2n=4x=32，2n=3x=24）(利容千，1989；杜武峰等，1993)。虽然在自然条件下能够开花，但因其小饱子败育空瘪，不能形成精子；大饱子及雌配子体发育异常，不能形成正常胚囊结构，故花而不实（董庆华等，1997）。因此，生产上仍然采用营养繁殖，不仅用种量大，繁殖系数低，而且种藠的贮藏和运输增加成本，限制了许多名优品种的大面积推广。营养繁殖还使病毒积累导致种性退化严重，产量和品质下降，严重影响其经济价值和食用性，给生产消费和出口创汇带来了严重的障碍，是目前生产上需要解决的问题。ThecultivatedspeciesofAlliumchinensisG.Donaremainlypolyploidyplantsliketriploidandtetraploid(2n=4x=32，2n=3x=24)(LiRongqian,1989;DuWufeng,etal.,1993).Althoughitcanblossomunderthenaturalcondition,itssmallsporesabortandareemptyandcannotformsperms;thedevelopmentofbigsporesandfemalegametophytesisabnormal,andnonormalembryosacstructurecanbeformed;asaresult,itcanonlyblossom,butisunabletofruit(DongQinghua,etal.,1997).Therefore,vegetativepropagationisstilladoptedinproduction,whichislargeinseedconsumptionandlowinreproductioncoefficient.Furthermore,thestorageandtransportationoftheseedsofAlliumchinensisG.Donwilladdcostwhichrestrictsthelarge-areapromotionofmanyfamouscultivatedvarieties.Also,vegetativepropagationmayfacilitytheaccumulationofvirus,causingtheseriousdegradationoftheseednature,thereductionofoutputandquality,whichwillseverelyinfluenceitseconomicvalueandedibilityandbringseriousobstaclesfortheproductionconsumptionandearningofforeignexchangethroughexport.Itisatpresentaproblemrequiredtobesolvedintheproduction.利用组织培养方法获得无毒或少毒再生植株，并在短时间内快速增殖，获得大量组培苗是解决这些问题的有效途径。最近几十年，组织培养技术在葱属植物的离体培养及研究中发挥了巨大作用，取得了令人瞩目的成绩，但目前利用组织培养技术获得藠头再生植株，国内外对这方面的研究很少,仅有鳞茎盘（傅德明等，2006；Xu等，2008）、茎尖（黄钊等，2006）组织培养成功的报道。因此，利用组织培养技术建立一套较为完整、系统的藠头脱毒、快繁体系，对其育种、种资创新将具有重要价值。Itisaneffectiveapproachtohandletheseproblemsbyutilizingtissueculturemethodtoobtainnon-toxicorlow-toxicregeneratedplantsandrealizerapidpropagationwithinashortperiodoftimesoastoobtainalargequantityofplantlets.Inrecentdecades,tissueculturetechnologyhasplayedasignificantroleintheinvitrocultureandresearchofalliumplants,andremarkableaccomplishmentshavebeenreached.However,atpresent,theresearchesontheutilizationoftissueculturetechnologyinobtainingAlliumchinensisG.Donregeneratedplantsathomeandabroadarestillinsufficient.Thereareonlyreportsconcerningthesuccessoftissuecultureinbasalplate(FuDeming,etal.,2006;Xu,etal.,2008)andstemtip(HuangZhao,etal.,2006).Therefore,toestablishasetofrelativelycompleteands