Fig. 4.

Schematic diagram of cells at the margin of a Coleochaete thallus. (A) Cell expansion is propelled by autonomous changes in turgor pressure (P) and wall softening. However, the extent and direction of growth of an individual cell is constrained by counterforces, which originate from surrounding cells and are transmitted throughout the tissue. (B) Cell-autonomous processes for regulating (i) the timing of division according to cell size and (ii) the plane of cell division according to the shape of the cell are sufficient to account for morphogenesis in Coloechaete.