Bringing the multicellular fern meristem into focus
Bringing the multicellular fern meristem into focus
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DOI：
10.1111/nph.13825
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发表时间：
2016-05-01
期刊：
影响因子：
9.4
通讯作者：
Vasco, Alejandra
中科院分区：
文献类型：
--
作者：
Ambrose, Barbara A.;Vasco, Alejandra
在植物中，分生组织负责产生新的器官，同时也维持全能性（Wolff，1759）。茎顶端分生组织的组织结构及其细胞组织化学的分带与维管植物所有侧生器官的生长发育直接相关。令人惊讶的是，所有的植物分生组织曾经被认为是由一个单一的顶端细胞组成（Nägeli，1845，1846），但随后的细胞组织化学研究表明，种子植物分生组织是多细胞的带状（Popham，1951; Gifford & Corson，1971）。种子植物分生组织的这一概念已经渗透到该领域，并且对于揭示其功能的分子遗传学是不可或缺的（Gaillochet et al.，2015年）。对蕨类植物分生组织的细胞组织化学分析也表明蕨类植物分生组织是多细胞的，具有带状分布（McAlpin &白色，1974;史蒂文森，1976 a，1978; Gifford，1983;白色& Turner，1995）。然而，蕨类分生组织由单个或几个顶端细胞原始细胞组成的经典观点仍然是书籍和发育遗传学研究中的流行观点（Harrison et al.，2005;佐野等人，2005; Tomescu，2010; Schneider，2013; Banks，2015; Frank等人，2015;植物本体论联盟（POC），2015;图1a）。这个单细胞分生组织模型的传播可以通过检查过去10年的不同科学来源得到最好的说明。与关注蕨类植物分生组织的解剖学的较旧的参考文献（McAlpin和白色，1974; Bierhorst，1977; Gifford，1983）不同，这些较新的参考文献在其分生组织的定义中没有详细说明。然而，许多引文，包括一个定义只是指大的顶端原始或原始，并没有讨论蕨类分生组织作为多细胞与环带。例如，在定义顶端细胞时，植物本体论联盟（Plant Ontology Consortium）--它目前正在努力产生一个描述所有植物的植物解剖学、形态学和发育阶段的受控词汇--明确地接受了蕨类分生组织由单个顶端起始点组成的想法：“顶端细胞只出现在芽轴顶端、叶顶端、根尖、叶状体顶端或一些蕨类植物中的原丝体的顶端。顶端生长是由位于顶端分生组织或植物器官顶端的单个分生组织细胞的分裂引起的，而不是由位于顶端分生组织顶端的一群分生组织细胞引起的。（植物本体论联盟（POC），2015）。此外，在一篇研究叶发育的论文中，Harrison et al.（2005）当讨论石松属植物卷柏的分生组织时，他们讨论的唯一细胞是顶端细胞：“顶端表面上的一条大细胞”（Harrison et al.，然后，在谈到蕨类植物薇菜时，他们说，“像卷柏一样，分生组织在表面有明显的顶端细胞，在分枝时分叉。”（Harrison等人，2005年，第512页）。类似地，在另一篇关于蕨类植物中I类KNOX基因功能的论文中，佐野等人（2004）在一篇关于蕨类植物中I类KNOX基因功能的论文中，（2005）解释说：“水蕨属孢子体的茎顶端分生组织含有一个四面体顶端细胞。”此外，在对蕨类植物形态特征的综述中，作者再次引用了经典的观点，指出：“无籽维管植物的生长顶端以不分层的顶端分生组织为特征，其中一个或几个顶端原始细胞，存在于分生组织的表面，负责组织的产生。这种近形维管植物特征与大多数种子植物顶端分生组织的分层性质形成对比（Tomescu，2010，pp. 74-75）和“蕨类植物表现出相当简单的有组织的顶端分生组织”（白色& Turner，1995; Imaichi 2008.
In plants, meristems are responsible for generating new organs while also maintaining totipotency (Wolff, 1759). The organization of the shoot apical meristem and its cytohistochemical zonation is directly related to the growth and development of all lateral organs in vascular plants. Surprisingly, all plant meristems were once thought to be composed of a single apical cell (Nägeli, 1845, 1846), but subsequent cytohistochemical studies demonstrated that seed plant meristems are multicellular with zonation (Popham, 1951; Gifford & Corson, 1971). This concept of the seed plant meristem has permeated the field and has been integral for unraveling the molecular genetics of its function (Gaillochet et al., 2015). Cytohistochemical analyses of fern meristems have also shown that the fern meristem is multicellular with zonation (McAlpin & White, 1974; Stevenson, 1976a, 1978; Gifford, 1983; White & Turner, 1995). However, the classical idea that the fern meristem is composed of a single or a few apical cell initials remains a prevailing view in books and developmental genetic studies (Harrison et al., 2005; Sano et al., 2005; Tomescu, 2010; Schneider, 2013; Banks, 2015; Frank et al., 2015; Plant Ontology Consortium (POC), 2015; Fig. 1a). The propagation of this unicellular meristem model can be best illustrated by examining different scientific sources from the last 10 years. Unlike older references that focused on the anatomy of fern meristems (McAlpin & White, 1974; Bierhorst, 1977; Gifford, 1983), these more recent references do not go into careful detail in their definition of the meristem. However, many of the citations that do include a definition simply refer to the large apical initial or initials and do not discuss the fern meristem as multicellular with zonation. For instance, in defining apical cells the Plant Ontology Consortium–which is a current effort to produce a controlled vocabulary describing plant anatomy, morphology and stages of development for all plants–clearly embraces the idea of a fern meristem consisting of a single apical initial:‘Apical cells occur only at the tip of a shoot axis apex, leaf apex, root apex, thallus apex, or protonema in bryophytes and some pteridophytes. Apical growth results from division of a single meristematic cell located at the tip of an apical meristem or plant organ, rather than from a population of meristematic cells located at the tip of an apical meristem.’(Plant Ontology Consortium (POC), 2015). Furthermore, in a paper investigating leaf development, Harrison et al.(2005) when discussing the meristem of the lycophyte Selaginella kraussiana, the only cells that they discussed are the apical cells:‘a strip of large cells on the surface of the apex’(Harrison et al., 2005, p. 511).Then, talking about the fern Osmunda cinnamomea, they state,‘As in Selaginella, the meristem has distinct apical cells on the surface, and bifurcates during branching.’(Harrison et al., 2005, p. 512). Similarly in another paper about the function of Class I KNOX genes in ferns, Sano et al.(2005) explain that:‘The shoot apical meristem of Ceratopteris sporophyte contains a single tetrahedral apical cell.’Moreover, in reviews on the morphological features of ferns, authors again evoke the classical view by stating that:‘The growing tips of seed-free vascular plants are characterized by unstratified apical meristems in which one or several apical initials, present at the surface of the meristem, are responsible for tissue generation. This plesiomorphic vascular plant character is contrasting with the stratified nature of most seed plant apical meristems’(Tomescu, 2010, pp. 74–75) and ‘Ferns show rather simple organized apical meristems’(White & Turner, 1995; Imaichi 2008 …