The architecture and growth dynamics of the oil palm root system were observed, described and analyzed through architectural analysis. Following a transitional juvenile phase, eight different morphological types of roots have been distinguished according to their developmental pattern and state of differentiation: the primary vertical roots (RI VB) and the primary horizontal roots (RI H), the secondary horizontal roots (RII H), upward growing vertical roots (RII VH) and downward growing vertical roots (RII VB), the superficial RIIIs) and the deep (RIIIp) tertiary roots and the quaternary roots (RIV). The relative position of these types of roots represents a morphological and functional unit of the root system, called "root architectural unit" of the oil palm. The identification of the edification sequence of these different roots allowed us to establish the basis of a mathematical formalization of the functioning of root meristems. The mathematical models used in this work were based on stochastic processes (graphs, automata, laws of probability). The processes of growth, branching and mortality and their geometrical parameters were formalized and put together in a synthetic model: the reference axis. Simulation provides tridimensional numerical mock-ups, the validation of which appears satisfactory. These models help to estimate root biomass and distribution, to locate and quantify the absorbing parts of roots and to assess the volume of soil explored by assimilating roots. These various applications offer a promising future in the study of carbon allocation patterns between above- and below-ground parts of plants, or the approach of the intricate phenomena of root competition. (Texte intégral)