Morphogenesis in Selaginella: III. Meristem determination and cell differentiation☆
[摘要] SelaginellawilldenoviiBakerisaprostratevascularcryptogamwithadorsiventralstem.Ateachmajorbranchingofthestemtipadorsalandaventralanglemeristemareformed.Theventralmeristembecomesdeterminedasarootandthedorsalmeristemasashoot.Indoleaceticacid(IAA)istransportedbasipetallyinthestemandhasbeenfoundtobetheregulatoryagentformeristemdeterminationbothinvitroandinvivo.Growthmeasurementsofintactplantsindicatedthatthesequenceofdevelopmentforeachstemunitisfrondexpansion,internodalelongation,ventralmeristemgrowthasaroot,anddorsalmeristemgrowthasashoot.Theprincipalexperimentalfindingsofthisstudyareasfollows.Triiodobenzoicacid(TIBA),aninhibitorofauxintransportaltersthenormalpatternofdevelopmentinintactplants,causingventralmeristemstodevelopasshootsanddorsalmeristemstodevelopprecociously.Dorsalmeristemsgrowninsterilecultureonanauxin-freemediumdevelopasshoots,butinthepresenceofIAAdevelopasroots.Meristemstransferredafterexcisionfromauxin-freetoplus-auxinmediumonsuccessivedaysshowedanincreasingtendencytodevelopasshoots,withmorethan50%doingsobyday5.Themitoticindexislowatthetimeofexcisionofthemeristem,risestoapeakonday5andthendeclines.
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[效力级别] [学科分类] 生物科学（综合）
[关键词] [时效性]
