Gelation of cells during the development of leaf and flower mesophyll tissue*

The development of complex plant tissues requires careful coordination of cell positions and interactions. In the spongy mesophyll tissue in leaves and flowers, cells form complex networks that maximize air conductance in leaves and minimize resource usage in flower petals. While these developmental processes are vital for plant fitness, little is known about the self-assembly process that generates such intricate structures. We investigate this process using explicitly deformable, sticky particles that self-assemble into porous yet rigid networks from initially dense packings. We investigate the effect of cell deformability and cell-cell adhesion on how maximally porous a system can become before losing rigidity. We compare our results to 3D X-ray microcomputed tomography scans of living leaf and plant tissue as well as continuum models of viscoelastic phase separation. Our studies indicate that the formation of optimally porous networks hinge upon a balance between cell-cell adhesion, cell wall bending energy and slow aging of the cell perimeter.