Abstract Although ferns are an important group for understanding leaf evolution, their developmental processes are still few understood. To better understand the organization of meristems and ontogeny of leaves in ferns, we studied their development in Elaphoglossum vagans (Mett.) Hieron., Lastreopsis amplissima (C. Presl) Tindale, Lomariopsis marginata (Schrad.) Kuhn, Mickelia scandens (Aubl.) R.C. Moran et al., Polybotrya cylindrica Kaulf., and Rumohra adiantiformis (G. Forst.) Ching, by using anatomical techniques. In addition, we observed herbarium specimens of those species, plus Elaphoglossum lingua (C. Presl) Brack, searching for unusual morphologies that may occur, that could represent a deviation from developmental processes here described. We propose hypotheses to explain these “natural mutants” based on known mechanisms of development. Shoot apical meristems of these species bear the typical tetrahedral cell with three dividing faces and the leaf apical meristem has two dividing faces. The leaf forms marginal meristems with enlarged initial cells, each of them bearing similarities to the leaf apical cell geometry and size, except in the simple-leaved fern Elaphoglossum vagans. Pinnae and segments primordia have grouped apical cells that are contiguous with their own marginal cells. In multi-pinnate leaves, one of these grouped apical cells in pinnae may enlarge and become similar to the leaf apical cell, indicating a reiterative process. The observed plants with unusual morphologies include plants with mixed reproductive identity, differential marginal growth, compromised apical growth, and reduced determinacy, supporting previous studies for leptosporangiate ferns. Apical and marginal cells of ferns may be homologous between them. Their characteristic geometry may allow specific cell divisions and their interconvertibility may drive the balance between apical and marginal growth. Unusual activity of these cells or changes in transcription factors may generate the observed abnormalities. A reiterative development in fern leaves supports the homology with shoots and the identity-in-parallel of their divisions.

中文翻译：

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一些具有不同解剖模式的蕨类植物（干蕨科和 Lomariopsidaceae）的叶子发育

摘要 虽然蕨类植物是了解叶片进化的重要类群，但其发育过程仍知之甚少。为了更好地了解蕨类植物分生组织的组织和叶子的个体发育，我们研究了它们在 Elaphoglossum vagans (Mett.) Hieron.、Lastreopsis amplissima (C. Presl) Tindale、Lomariopsis marginata (Schrad.) Kuhn、Mickelia scandens (Aubl.) 中的发育。 ) RC Moran 等人、Polybotrya cylindrica Kaulf. 和 Rumohra adiantiformis (G. Forst.) Ching，通过使用解剖学技术。此外，我们观察了这些物种的植物标本馆标本，以及 Elaphoglossum lingua (C. Presl) Brack，寻找可能出现的异常形态，这可能代表与此处描述的发育过程的偏差。我们根据已知的发育机制提出假设来解释这些“自然突变体”。这些物种的茎尖分生组织具有典型的四面体细胞，具有三个分割面，叶尖分生组织具有两个分割面。叶子形成边缘分生组织，初始细胞扩大，每个细胞都与叶尖细胞的几何形状和大小相似，除了单叶蕨类植物 Elaphoglossum vagans。耳廓和原基节具有与它们自己的边缘细胞相邻的顶端细胞分组。在多羽状叶中，羽片中这些成组的顶端细胞之一可能会扩大并变得与叶顶端细胞相似，表明一个重复的过程。观察到的具有异常形态的植物包括具有混合生殖特性、边缘生长差异、顶端生长受损和确定性降低的植物，支持先前对钩孢子蕨类植物的研究。蕨类植物的顶端细胞和边缘细胞可能是同源的。它们的特征几何形状可能允许特定的细胞分裂，它们的相互转换可能会推动顶端和边缘生长之间的平衡。这些细胞的异常活动或转录因子的变化可能会产生观察到的异常。蕨叶的反复发展支持与枝条的同源性和它们分裂的平行同一性。