A ROOT-MORPHOLOGY BASED SIMULATION FOR PLANT-SOIL MICROBIAL ECOSYSTEMMODELING

A simulation model is presented that produces and manipulates computer representations of plant root microbial ecosystems. The root system i s described as a collection of nodes. A node records a position in thr ee-dimensional space and may represent the origin of another root, a b end, or some change in the root's microbial status. Disease lesions, c losely associated microbial populations such as mycorrhizal fungi, and free soil microbial populations may also be represented. A multi-dime nsional matrix structure provides a useful conceptual framework for th e numerous stochastic functions required by the model. Procedures for building the node-based root map, and for simulating root growth and m icrobial interaction, are presented in terms of such a matrix, in conj unction with the necessary manipulations of the node lists which repre sent the root system. This paper assesses the practicality of the appr oach described, which appears to be feasible and potentially useful. T he model is considered as a step towards a generic framework for model ling root-architecture and the spatial structure of associated microbi al ecosystems. The model has been successfully applied to a simulation of a Pinus radiata/Armillaria spp. pathosystem. (C) 1997 Elsevier Sci ence B.V.