Abstract:
Plasmodesmata (PD) serve for the exchange of information in form of miRNA, proteins, and mRNA between adjacent cells in the course of plant development. This fundamental role of PD is well established in angiosperms but has not yet been traced back to the evolutionary ancient plant taxa where functional studies lag behind studies of PD structure and ontogenetic origin. There is convincing evidence that the ability to form secondary (post-cytokinesis) PD, which can connect any adjacent cells, contrary to primary PD which form during cytokinesis and link only cells of the same lineage, appeared in the evolution of higher plants at least twice: in seed plants and in some representatives of the Lycopodiophyta. The (in)ability to form secondary PD is manifested in the symplasmic organization of the shoot apical meristem (SAM) which in most taxa of seedless vascular plants differs dramatically from that in seed plants. Lycopodiophyta appear to be suitable models to analyze the transport of developmental regulators via PD in SAMs with symplasmic organization both different from, as well as analogous to, that in angiosperms, and to understand the evolutionary aspects of the role of this transport in the morphogenesis of vascular plant taxa.
摘要:
质粒(PD)用于miRNA形式的信息交换,蛋白质,在植物发育过程中相邻细胞之间的mRNA。PD的这种基本作用在被子植物中已得到很好的确立,但尚未追溯到进化的古老植物分类群,其中功能研究落后于PD结构和个体发育起源的研究。有令人信服的证据表明,形成继发性(胞质分裂后)PD的能力,可以连接任何相邻的细胞,与在胞质分裂期间形成并仅连接相同谱系的细胞的原代PD相反,出现在高等植物的进化中至少两次:在种子植物和Lycopodiphanta的一些代表中。形成次生PD的(in)能力表现在芽顶端分生组织(SAM)的共生组织中,该组织在大多数无核维管植物的分类单元中与种子植物中的分类单元有很大不同。Lycopodiophyta似乎是分析发育调节剂通过PD在具有共生组织的SAM中运输的合适模型,以及类似于,在被子植物中,并了解这种运输在维管植物分类群形态发生中的作用的进化方面。