Hormone-mediated pattern formation in seedling of plants: a competitive growth dynamics model

An ecologically relevant pattern formation process mediated by hormonal int eractions among growing seedlings is modeled based on the experimental obse rvations on the effects of indole acetic acid, which can act as an inhibito r and activator of root growth depending on its concentration. In the absen ce of any lateral root with constant hormone-sensitivity, the edge effect p henomenon is obtained depending on the secretion rate of hormone from the m ain root. Introduction of growth-stage-dependent hormone-sensitivity drasti cally amplifies the initial randomness, resulting in spatially irregular ma croscopic patterns. When the lateral root growth is introduced, periodic pa tterns are obtained whose periodicity depends on the length of lateral root s. The growth-stage-dependent hormone-sensitivity and the lateral root grow th are crucial for macroscopic periodic-pattern formation.