School of Biosciences, Cardiff University, Cardiff, Wales CF10 3AX, United Kingdom.
Plant Cell. 2012 Oct;24(10):3907-19. doi: 10.1105/tpc.112.102194. Epub 2012 Oct 30.
The shoot apical meristem (SAM) is a small population of stem cells that continuously generates organs and tissues. This review covers our current understanding of organ initiation by the SAM in Arabidopsis thaliana. Meristem function and maintenance involves two major hormones, cytokinins and auxins. Cytokinins appear to play a major role in meristem maintenance and in controlling meristematic properties, such as cell proliferation. Self-organizing transport processes, which are still only partially understood, lead to the patterned accumulation of auxin at particular positions, where organs will grow out. A major downstream target of auxin-mediated growth regulation is the cell wall, which is a determinant for both growth rates and growth distribution, but feedbacks with metabolism and the synthetic capacity of the cytoplasm are crucial as well. Recent work has also pointed at a potential role of mechanical signals in growth coordination, but the precise mechanisms at work remain to be elucidated.
茎尖分生组织（SAM）是一小群干细胞，它们不断产生器官和组织。本篇综述涵盖了我们目前对拟南芥 SAM 中器官起始的理解。分生组织的功能和维持涉及两种主要激素，细胞分裂素和生长素。细胞分裂素似乎在维持分生组织和控制分生组织特性（如细胞增殖）方面发挥着主要作用。自组织的运输过程，尽管仍只是部分理解，导致生长素在特定位置的模式积累，而器官将从这些位置生长出来。生长素介导的生长调控的一个主要下游靶标是细胞壁，它是决定生长速度和生长分布的因素，但与代谢和细胞质的合成能力的反馈也至关重要。最近的工作还指出了机械信号在生长协调中的潜在作用，但作用的确切机制仍有待阐明。
