Graduate School of Science, The University of Tokyo, Science Building #2, 7-3-1, Hongo, Tokyo 113-0033, Japan.
Plant Cell. 2021 Oct 11;33(10):3194-3206. doi: 10.1093/plcell/koab190.
Leaf organogenesis is governed by the spatiotemporal activity of the leaf meristem, which has far greater mitotic activity than the shoot apical meristem. The two types of leaf meristems, the plate meristem and the marginal meristem, are distinguished by the location and longevity of their cell proliferative activity. Most leaf lamina outgrowth depends on the plate meristem. The presence of the marginal meristem was a matter of debate in classic anatomy, but recent genetic analyses of leaf growth in Arabidopsis thaliana confirmed its short-lived activity. Several genes key for the regulation of the two meristem types have been identified, and at least superficially, the systems appear to function independently, as they are regulated by different transcription factors and microRNAs. However, many of the details of these regulatory systems, including how the expression of these key factors is spatially regulated, remain unclear. One major unsolved question is the relationship between the plate meristem and the marginal meristem. Here, I present an overview of our current understanding of this topic and discuss questions that remain to be answered.
叶片器官发生由叶片分生组织的时空活性控制，叶片分生组织的有丝分裂活性远远大于茎尖分生组织。两种类型的叶片分生组织，即原基板分生组织和边缘分生组织，因其细胞增殖活性的位置和持续时间而有所区别。大多数叶片的延伸生长取决于原基板分生组织。边缘分生组织的存在在经典解剖学中曾存在争议，但最近对拟南芥叶片生长的遗传分析证实了其短暂的活性。已经鉴定出几个对两种分生组织类型调控至关重要的基因，至少从表面上看，这些系统似乎独立运作，因为它们受到不同转录因子和 microRNAs 的调控。然而，这些调控系统的许多细节，包括这些关键因子的表达如何受到空间调控，仍然不清楚。一个主要未解决的问题是原基板分生组织和边缘分生组织之间的关系。在这里，我概述了我们目前对这一主题的理解，并讨论了仍有待回答的问题。
