A FUNCTIONAL-STRUCTURAL MODEL OF CHRYSANTHEMUM FOR PREDICTION OF ORNAMENTAL QUALITY

Abstract

An integration of structural and physiological models is used to simulate 3D plant growth and visual appearance of cut chrysanthemum, reacting on environmental factors. Measurements to calibrate the model include 3D data of digitised plants as well as a number of measurements and observations on harvested plants, including biomass per organ. The structural module is based on the L-systems algorithm. This L-system calculates temperature and light driven development, branching pattern, and flower formation. In this 3D structural model existing rules for physiological processes are incorporated, enabling calculation of carbon dynamics. A 3D radiosity method is used to calculate light absorption of every organ (leaf) at an hourly basis. Hourly photosynthesis per leaf is calculated according to the biochemical model of Farquhar taking into account absorbed light, CO2, and temperature at hourly intervals. A relative sink strength approach is used to distribute the available assimilates among organs at a daily basis. Simulated growth response to temperature is based on various trial data. Modelling of light interception and photosynthesis is currently tested for one plant density only. Since the 3D crop consists of a set of individual plants, simulation of plant to plant competition for light is enabled. The model is able to visualise different flower qualities in terms of flower number, flower size and branching patterns per plant. The results show the effects of local growth of organs on the structure and ornamental quality at plant level.