Figure 3.

Cell division patterns during stomatogenesis in dark-grown (first three stages) and light-grown (all four stages) cucumber hypocotyls. SPC, stomatal progenitor cell; GMC, guard mother cell; GC, guard cell; SMC, subsidiary mother cell; SC, subsidiary cell. In light-grown seedlings, transverse division of the stomatal precursor cell produces an apical guard mother cell and a basal subsidiary mother cell. Division of all cells surrounding the guard mother cell generates six subsidiary cells. In contrast, in dark-grown seedlings, the basal sibling of the GMC, as well as other surrounding subsidiary mother cells, do not divide and the stomatal development arrests at the third stage.