This thesis considers the status of computational modelling in plant biology. After a brief introduction to modelling in biology, the reader is introduced to different approaches and tool. Among them, cell-based modelling is chosen to first model the effect of cell wall mechanics over tissue growth, and then xylogenesis of a generic conifer is simulated. In order to do so, the VirtualLeaf modelling framework has been used and extended with a description of the mechanical effects of thickness over cell dynamics. The frameworks proved itself a good tool for modeling such dynamics, and the output of the simulations suggest that tissue properties like growth anisotropy and proliferation rate (in the first case) and early- to latewood transition (in the second case) could be strongly linked to mechanical cell-autonomous properties and cell-cell interaction