Root Typ:: a generic model to depict and analyse the root system architecture

Dynamic models of root system development and architecture integrate various developmental processes and let simulate multiple dynamic interactions. They are recognised as valuable tools to study the soil - plant - atmosphere continuum. In the recent years, some models have emerged from fractal descriptions. Others arose from developmental approaches but most efforts met little success for genericity. Among the difficulties with models are their growing complexity and they inability to detail evenly all important mechanisms often due to a deficit of independent and suitable data for model testing. We propose here a generic model called 'Root Typ' dedicated to quantitative and global analyses of root system architectures and simplified representation of architectural diversity. It aims at ( i) detailing evenly a large range of developmental processes, (ii) generalising the concept of root type and (iii) representing in a very simplified way soil effects on developmental processes. The model implements several developmental processes including: root emission, axial and radial growth, sequential branching, reiteration, transition, decay and abscission, which are all discussed in details. Finally, it's ability to mimic a diversity of root architectures is tested against representative root systems depicted in the book of Kutschera ( 1960) which represents an independent database collected on a large number of plant species and soil conditions, and gives an overall synthetic view upon root systems.