Coupling water fluxes with cell wall mechanics in a multicellular model of plant development

The growth of plant organs is a complex process powered by osmosis that attracts water inside the cells; this influx induces simultaneously an elastic extension of the walls and pressure in the cells, called turgor pressure; above a threshold, the walls yield and the cells grow. Based on Lockhart’s seminal work, various models of plant morphogenesis have been proposed, either for single cells, or focusing on the wall mechanical properties. However, the synergistic coupling of fluxes and wall mechanics has not yet been fully addressed in a multicellular model. This work lays the foundations of such a model, by simplifying as much as possible each process and putting emphasis on the coupling itself. Its emergent properties are rich and can help to understand plant morphogenesis. In particular, we show that the model can display a new type of lateral inhibitory mechanism that amplifies growth heterogeneities due e.g to cell wall loosening.

植物器官的生长是由渗透作用驱动的复杂过程：渗透作用将水分吸入细胞内部；该水分流入同时引发细胞壁的弹性伸展以及细胞内压力（turgor pressure，膨压）的产生；当压力超过阈值时，细胞壁会发生屈服，细胞随即生长。基于洛克哈特（Lockhart）的开创性研究，学界已提出多种植物形态发生模型，这些模型要么针对单个细胞，要么聚焦于细胞壁的机械特性。然而，在多细胞模型中，物质流与细胞壁力学的协同耦合机制尚未得到充分阐释。本研究通过尽可能简化各过程并重点聚焦耦合机制本身，为该类模型奠定了基础。该模型具备丰富的涌现特性，有助于推动我们对植物形态发生过程的理解。尤为重要的是，本研究证明该模型可呈现一种新型侧向抑制机制，该机制能够放大因细胞壁松弛等因素引发的生长异质性。