Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCBL, INRAE, CNRS, INRIA 46 Allée d'Italie, 69364, Lyon, France.
Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences and Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland.
Nat Commun. 2024 Aug 13;15(1):6944. doi: 10.1038/s41467-024-51099-x.
In multicellular organisms, tissue outgrowth creates a new water sink, modifying local hydraulic patterns. Although water fluxes are often considered passive by-products of development, their contribution to morphogenesis remains largely unexplored. Here, we mapped cell volumetric growth across the shoot apex in Arabidopsis thaliana. We found that, as organs grow, a subpopulation of cells at the organ-meristem boundary shrinks. Growth simulations using a model that integrates hydraulics and mechanics revealed water fluxes and predicted a water deficit for boundary cells. In planta, a water-soluble dye preferentially allocated to fast-growing tissues and failed to enter the boundary domain. Cell shrinkage next to fast-growing domains was also robust to different growth conditions and different topographies. Finally, a molecular signature of water deficit at the boundary confirmed our conclusion. Taken together, we propose that the differential sink strength of emerging organs prescribes the hydraulic patterns that define boundary domains at the shoot apex.
在多细胞生物中，组织的生长会产生新的水分汇，从而改变局部水力模式。尽管水分流动通常被认为是发育的被动副产物，但它们对形态发生的贡献在很大程度上仍未得到探索。在这里，我们绘制了拟南芥茎尖的细胞体积生长图。我们发现，随着器官的生长，器官-分生组织边界处的一部分细胞会收缩。使用一种将水力学和力学相结合的模型进行的生长模拟揭示了水分流动，并预测了边界细胞的水分亏缺。在植物体内，一种水溶性染料优先分配到快速生长的组织中，而无法进入边界区域。在快速生长的组织旁边，细胞的收缩对不同的生长条件和不同的地形也具有很强的稳健性。最后，边界处水分亏缺的分子特征证实了我们的结论。总之，我们提出，新兴器官的不同汇强度规定了茎尖边界区域的水力模式。
