3 - The stem cell concept applied to shoot meristems of higher plants

Abstract

This chapter applies stem cell concept to shoot meristems of higher plants. The remarkable regenerative ability of mere slices of the meristem is consistent with an “all potential founder cell” concept in the vegetative meristem. Clearly, in normal development not all cells in the meristem are founders. More likely is the notion that GO cells in the central or the axial zone of the shoot meristem are true founders and their activation into the cell cycle, as they transit from the central to the peripheral zone, is a key regulatory event. However, paradoxically, in some species such cells cannot be located. The task of locating founder cells in floral shoot meristems may seem easier in a determinate developing structure. Not all cells within a molecular domain develop as a floral organ. One of the key interactions must be molecular controls of the cell cycle which predispose cells to divide as a cohort or cellular domain coupled to the expression of the organ identity genes. This chapter explains the morphology of the vegetative shoot apex. It also discusses cell cycle heterogeneity in vegetative shoot meristems. The stem cell concept for vegetative meristems is explained in detail.