Wu Xiao, Yan An, Liu Xing, Zhang Shaoling, Zhou Yun
Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907, USA.
Purdue Centre for Plant Biology, Purdue University, West Lafayette, Indiana 47907, USA.
Quant Plant Biol. 2022 Nov 17;3:e25. doi: 10.1017/qpb.2022.21. eCollection 2022.
Meristems in land plants share conserved functions but develop highly variable structures. Meristems in seed-free plants, including ferns, usually contain one or a few pyramid-/wedge-shaped apical cells (ACs) as initials, which are lacking in seed plants. It remained unclear how ACs promote cell proliferation in fern gametophytes and whether any persistent AC exists to sustain fern gametophyte development continuously. Here, we uncovered previously undefined ACs maintained even at late developmental stages in fern gametophytes. Through quantitative live-imaging, we determined division patterns and growth dynamics that maintain the persistent AC in , a representative fern. The AC and its immediate progenies form a conserved cell packet, driving cell proliferation and prothallus expansion. At the apical centre of gametophytes, the AC and its adjacent progenies display small dimensions resulting from active cell division instead of reduced cell expansion. These findings provide insight into diversified meristem development in land plants.
陆地植物中的分生组织具有保守的功能，但结构高度可变。无种子植物（包括蕨类植物）中的分生组织通常含有一个或几个呈金字塔形/楔形的顶端细胞（ACs）作为起始细胞，而种子植物中则没有。目前尚不清楚顶端细胞如何促进蕨类配子体中的细胞增殖，以及是否存在任何持续存在的顶端细胞来持续维持蕨类配子体的发育。在这里，我们发现了即使在蕨类配子体发育后期仍维持存在的先前未定义的顶端细胞。通过定量实时成像，我们确定了在一种代表性蕨类植物中维持持续存在的顶端细胞的分裂模式和生长动态。顶端细胞及其直接后代形成一个保守的细胞群，驱动细胞增殖和原叶体扩展。在配子体的顶端中心，顶端细胞及其相邻后代由于活跃的细胞分裂而非细胞扩展减少而呈现出较小的尺寸。这些发现为陆地植物中多样化的分生组织发育提供了见解。
