Abstract

In this work, an agent-based functional-structural model of growth simulation for Orange tree is presented. This simulation model is named ORASIM (ORAnge tree SIMulation). In ORASIM, functions such as carbon/water acquisitions, expenses and their dynamics are embedded into individual metamer/root agents with detailed geometries and 3D shapes. The organization of metamer/root agent’s nested-list forms a growing, three-dimensional orange tree structure. After model parameterization using field data of orange tree growth, main features of functioning on whole tree level, that is, morphological and physiological responses to environmental heterogeneity have been investigated. It demonstrated that, using ORASIM, the phenotypic plasticity of orange tree can be fully emerged from interactions between agents. Moreover, the outputs of ORASIM, such as the characters of shape, branch pattern and other physiological features, show a good agreement between the simulation and the real growth orange trees.

Key words: Emergent property, metamer, autonomous agents, digital orange tree, simulation.