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1、棉花體細(xì)胞胚發(fā)生過程的組織細(xì)胞學(xué)觀察曹景林,張獻(xiàn)龍*,楊細(xì)燕,鄧鋒林,譚家福,郝娟(華中農(nóng)業(yè)大學(xué)作物遺傳改良國家重點實驗室,武漢430070)摘要:以陸地棉品種Coker201下胚軸為外植體誘導(dǎo)愈傷組織,并以介于30-50目篩之間的胚性愈傷細(xì)胞團(tuán)為材料進(jìn)行單個細(xì)胞團(tuán)培養(yǎng),采用石蠟切片法觀察棉花愈傷組織誘導(dǎo)和分化過程及體細(xì)胞胚發(fā)生和發(fā)育過程。結(jié)果顯示棉花胚性愈傷組織有下胚軸兩端發(fā)生、內(nèi)發(fā)生、非胚性細(xì)胞轉(zhuǎn)化、外發(fā)生和腺體處發(fā)生5種形成途徑,其中兩端發(fā)生和內(nèi)發(fā)生是主要的形成方式;棉花體細(xì)胞胚存在單細(xì)胞起源,多為表面發(fā)生。棉花體細(xì)胞
2、胚發(fā)育過程中最關(guān)鍵的事件似乎是極性的建立、頂端分生組織的形成以及前形成層的分化和生長軸變化。球形胚時期表皮原層的分化標(biāo)志著體細(xì)胞胚結(jié)構(gòu)分化的開始。初始前形成層的形成是體細(xì)胞胚形態(tài)轉(zhuǎn)變的第一個信號。球形胚內(nèi)部等徑細(xì)胞軸向延長,接著前形成層生長軸發(fā)生變化,這些是心形胚或橢圓形體胚中的重要事件。魚雷形胚基本分生組織中液泡的出現(xiàn)開始了組織分化的過程。對一些停滯發(fā)育的球形胚和魚雷形胚的解剖檢查表明,極性建立可能是決定體細(xì)胞胚能否萌發(fā)的關(guān)鍵因素。關(guān)鍵詞:棉花;體細(xì)胞胚胎發(fā)生;組織細(xì)胞學(xué)基金項目:教育部新世紀(jì)人才支持計劃(NCET-04
3、-0740)作者簡介:曹景林(1967-),男,博士,遺傳育種專業(yè),現(xiàn)在湖北省煙草科研所工作。*通訊作者(Correspondingauthor):張獻(xiàn)龍,男,教授,博士生導(dǎo)師。E-mail:xlzhang@mail.hzau.edu.cnHisto-cytologicalObservationofSomaticEmbryogenesisinCotton(GossypiumhirsutumL.)CaoJing-lin,ZhangXian-long,YangXi-yan,DengFeng-lin,TanJia-fu,HaoJu
4、an(NationalKeyLaboratoryofCropGeneticImprovement,HuazhongAgriculturalUniversity,430070,Wuhan,Hubei,China)Abstract:CalliwereinducedfromhypocotylexplantsofcottoncultivarCoker201,andindividualembryogeniccellclusterswith30–50meshsieve,whichisolatedfromembryogenicsuspen
5、sioncultures,werecultured.Thedevelopmentofthecalliandsinglefew-celledaggregateswasobservedthroughparaffinsections.Theresultsrevealed5pathwaysofembryogeniccallioriginationincludingoriginationfrombothendsofhypocotyls,originationininner,differentiationfromnon-embryoni
6、ccells,originationfromoutercellsofcalli,andoriginationinthesurroundingofgland.Amongthese,theoriginationfrombothendsofhypocotylsandininnerwerethemostimportantpathways.Cottonsomaticembryosoriginatedfromindividualembryogeniccells,whichwereinexteriorofembryogeniccallii
7、nmostcases.Themostcriticaleventsappearedtobetheestablishmentofapical-basalpatternsofsymmetry,formationofapicalmeristems,anddifferentiationandaxialchangeofprocambiumduringthedevelopmentofcottonsomaticembryos.Differentiationoftheprotodermlayermarkedthebeginningofthes
8、tructuraldifferentiationinglobularstage.Incipientprocambiumformationwasthefirstsignofsomaticembryotransition.Axialelongationofinnerisodiametricce