SIMROOT - MODELING AND VISUALIZATION OF ROOT SYSTEMS

SimRoot, a geometric simulation model of plant root systems, is descri bed. This model employs a data structure titled the Extensible Tree, w hich is well suited to the type of data required to model root systems . As implemented on Silicon Graphics workstations, the data structure and visualization code provides for continuous viewing of the simulate d root system during growth. SimRoot differs from existing models in t he explicit treatment of spatial heterogeneity of physiological proces ses in the root system, and by inclusion of a kinematic treatment of r oot axes. Examples are provided of the utility of the model in estimat ing the fractal geometry of simulated root systems in 1, 2, and 3 dime nsional space. We envision continued development of the model to incor porate competition from neighboring root systems, linkage with crop si mulation models to simulate root-shoot interactions, explicit treatmen t of soil heterogeneity, and plasticity of root responses to soil fact ors such as presence of mycorrhizal associations.