Colloque

Lateral emergence and apex restoration: a modelling by a geometrical automaton

Hervé Le Guyader

Michel Ferré

Membre a labase

Hervé Le Guyader

Résumé du colloque

We present the construction and the functioning of a geometrical automaton as a model for the ramification in Dicotyledons. We begin with the characterization of the minimal geometrical structures which summarize the components of the cell surface. They suggest geometrical transformations as the dynamics of the development. The structures which are invariant under those transformations represent the stable states of the system. The functioning of the geometrical automaton allows the integration of the connections between the deformation and the cell wall. It appears at work when the system switches from one stable state to another, the apical cells turn from a stable state into another one despite a sudden shift of the direction of their elongation. After a lateral emergence, the apex is restored through the same process. Finally, we show that the sequence of the local events renders an account of the angles of phyllotaxis.