Floral patterning in Sunflower – folding in a confined space

Siobhan Braybrook

Theories of organ patterning have a long history, from geometrical, to chemical, to mechanical bases. Recent research, both experimental and mathematical, indicates that the most complete patterning mechanisms likely encompasses all of the proposed mechanisms. The shoot apical meristem comprises a central zone of ‘stem cells’ and a peripheral zone where organs form and differentiate. The controlled accumulation of the phytohormone auxin, by transport proteins of the PIN family, triggers cell expansion and differentiation within the peripheral zone. The link between auxin and cell expansion has also been studied extensively. Most recently, it has been established that auxin triggers changes in cell wall mechanical properties that are necessary for organ formation. It also appears that the auxin transport machinery may be sensitive to tissue stresses, and possibly the mechanical state of the cell wall.

Proceedings of the 6th Mathematics in the Plant Sciences Study Group