Plant stem cells organisation and function : the shoot apical meristem in Arabidopsis

Shoot development in higher plants is characterised-by continuous organ for mation from groups of stem cells established during embryogenesis: the shoo t apical meristem. The shoot meristem must maintain a central population of dividing cells and allow cell differentiation in lateral organs. The exist ence of distinct functional, domains corresponding to these two roles has b een postulated from extensive histological studies of the shoot meristem. D uring the last decade, genetic analysis performed in Arabidopsis lead to th e identification of several mutants affected in the different meristem func tions. Cloning and expression pattern studies of the corresponding genes ha ve confirmed and elaborated the classical models of meristem cells organisa tion.. Based on the meristem regulators interactions and on cell-cell commu nication mechanisms instrumental in meristem function, the first basis in t he understanding of the dynamic of these highly ordered structures. can be drawn.