The dynamic model of plant growth GreenLab describes plant architecture and functional
growth at the level of individual organs. Structural development is controlled by formal
grammars and empirical equations compute the amount of biomass produced by the plant, and
its partitioning among the growing organs, such as leaves, stems and fruits. The number of
organs initiated at each time step depends on the trophic state of the plant, which is
evaluated by the ratio of biomass available in plant to the demand of all the organs. The
control of the plant organogenesis by this variable induces oscillations in the simulated
plant behaviour. The mathematical framework of the GreenLab model allows to compute the
conditions for the generation of oscillations and the value of the period according to the
set of parameters. Two case-studies are presented, corresponding to emergence of
oscillations associated to fructification and branching.
Similar alternating patterns are
commonly reported by botanists. In this article, two examples were selected: alternate
patterns of fruits in cucumber plants and alternate appearances of branches in
Cecropia trees. The model was calibrated from experimental data
collected on these plants. It shows that a simple feedback hypothesis of trophic control
on plant structure allows the emergence of cyclic patterns corresponding to the observed
ones.