Branching Models Consisting of Two Principles: Phyllotaxis and Effect of Gravity

Hisao Honda¹* and Hiroaki Hatta²

¹Hyogo University, Kakogawa, Hyogo 675-0195, Japan
²Tsukuba Botanical Garden, National Science Museum, Amakubo 4-1, Tsukuba 305-0005, Japan
*E-mail address: hihonda@hyogo-dai.ac.jp

(Received October 19, 2004; Accepted December 16, 2004)

Keywords: Branching, Computer Simulation, Gravity, Phyllotaxis, Tree

Abstract. Geometric branching models in which a mother branch generates daughter branches in 3D-space have been created to simulate tree-shapes of respective species. The branching models consist of two principles: the phyllotaxis and the effect of gravity, and computer simulations are made by combinations of one of the phyllotaxes (spiral, distichous, pseudo-whorled and decussate) with one of the effects of gravity (change of shoot-direction, restriction of shoot-growth, direction-change of branching plane, and sympodial branching). Results of simulations resemble real plants. The present general branching system with variety of combinations of intrinsic principles of phyllotaxis and environmental factor of gravity will help us to understand in detail how genetic information contributes to produce particular crown shapes under natural conditions.