背景回顾：In multicellular organisms, sexual reproduction requires the separation of the germline from the soma. In flowering plants, the female germline precursor differentiates as a single spore mother cell (SMC) as the ovule primordium forms. 

主要研究：Here, we explored how organ growth contributes to SMC differentiation. 

结果1-细胞3D图：We generated 92 annotated 3D images at cellular resolution in Arabidopsis. We identified the spatio-temporal pattern of cell division that acts in a domain-specific manner as the primordium forms.

结果2-模拟建模：Tissue growth models uncovered plausible morphogenetic principles involving a spatially confined growth signal, differential mechanical properties, and cell growth anisotropy.

结果3-提出假说：Our analysis revealed that SMC characteristics first arise in more than one cell but SMC fate becomes progressively restricted to a single cell during organ growth. 

结果4-突变体验证：Altered primordium geometry coincided with a delay in the fate restriction process in katanin mutants. 

结论：Altogether, our study suggests that tissue geometry channels reproductive cell fate in the Arabidopsis ovule primordium.

 摘 要 

在多细胞生物中，有性生殖需要生殖细胞从体细胞分离出来。在有花植物中，随着胚珠原基的形成，雌性生殖细胞前体细胞会分化形成单个的孢子母细胞（SMC）。本文中，作者研究了器官生长如何作用于孢子母细胞的分化。作者以拟南芥为材料，共获得了细胞层面、不同发育时期的胚珠原基3D结构图。结果发现，在原基形成时细胞分裂的时空模式以一种局域特异性的方式呈现。组织生长模型揭示了一个貌似合理的形态发生准则，包括空间受限的生长信号、差异化的力学性能和细胞生长的各向异性。作者的研究显示，带有SMC特性的细胞最早可能在多个细胞中出现，但是随着器官的发育，SMC命运逐步聚缩到其中某个单个细胞中。在katanin突变体中，原基的几何特性发生改变，同时SMC的命运聚缩过程也发生了延迟（甚至最终出现多个SMC）。综上，本文的研究揭示了在拟南芥胚珠原基中，组织的几何特征引导了生殖细胞命运的决定。