Figure 2.

Mechanical forces as positional dependent information in the formation of periodic structures in plants and animals. (A) In vertebrates, the formation of pigment patterns is determined by attraction/repulsion of chromatocytes and the deformation of the mesenchyme that generate tension tracks through which cells migrate. (B) In plants, the enhancement of cell wall and tissue elasticity by auxin creates undulations at the SAM surface. Furthermore, auxin regulates genetic programs that promote cell proliferation and differentiation into the different organ primordia. The modification of the mechanical field serves as positional information for the polarization of the PIN auxin efflux transporters. In both examples, long-range forces caused by changes in the mechanical field have a delimited range of action which is indicated by the periodicity of patterns.