Teeri Teemu H, Uimari Anne, Kotilainen Mika, Laitinen Roosa, Help Hanna, Elomaa Paula, Albert Victor A
Gerbera Laboratory, Department of Applied Biology, PO Box 27, 00014 University of Helsinki, Finland.
J Exp Bot. 2006;57(13):3445-55. doi: 10.1093/jxb/erl181. Epub 2006 Oct 5.
Flowering plants go through several phases between regular stem growth and the actual production of flower parts. The stepwise conversion of vegetative into inflorescence and floral meristems is usually unidirectional, but under certain environmental or genetic conditions, meristems can revert to an earlier developmental identity. Vegetative meristems are typically indeterminate, producing organs continuously, whereas flower meristems are determinate, shutting down their growth after reproductive organs are initiated. Inflorescence meristems can show either pattern. Flower and inflorescence development have been investigated in Gerbera hybrida, an ornamental plant in the sunflower family, Asteraceae. Unlike the common model species used to study flower development, Gerbera inflorescences bear a fixed number of flowers, and the architecture of the flowers differ in that Gerbera ovaries are inferior (borne below the perianth). This architectural difference has been exploited to show that floral meristem determinacy and identity are spatially and genetically distinct in Gerbera, and we have shown that a single SEPALLATA-like MADS domain factor controls both flower and inflorescence meristem fate in the plant. Although these phenomena have not been directly observed in Arabidopsis, the integrative role of the SEPALLATA function in reproductive meristem development may be general for all flowering plants.
开花植物在正常茎生长和花器官实际形成之间要经历几个阶段。营养分生组织逐步转变为花序分生组织和花分生组织的过程通常是单向的，但在某些环境或遗传条件下，分生组织可以恢复到较早的发育状态。营养分生组织通常是不确定的，能持续产生器官，而花分生组织是确定的，在生殖器官开始形成后就停止生长。花序分生组织可以表现出这两种模式。人们已经在非洲菊（菊科向日葵族的一种观赏植物）中研究了花和花序的发育。与用于研究花发育的常见模式物种不同，非洲菊的花序上花的数量是固定的，而且花的结构有所不同，因为非洲菊的子房是下位的（着生于花被下方）。这种结构差异已被用于表明，在非洲菊中花分生组织的确定性和特征在空间和遗传上是不同的，并且我们已经表明，一个单一的类SEPALLATA MADS结构域因子控制着该植物中花和花序分生组织的命运。尽管在拟南芥中尚未直接观察到这些现象，但SEPALLATA功能在生殖分生组织发育中的整合作用可能对所有开花植物来说都是普遍存在的。
