Hydroponic axenic culture conditions, in which the physical culture support of root growth consists of glass beads, are necessary to study physiological processes such as root exudation or absorption. The effects of the mechanical constraint induced by glass beads on the architectural evolution of the root system of young maize plants were examined. A reduction in length of all roots (seminal and nodal), an increase in seminal root diameter and a modification of order 2 root branching were observed. The root biomass was not affected (except for 16-day-old plants) but the total root area was reduced. The shoot growth was significantly decreased by the mechanical constraint.Les conditions de culture hydroponiques steriles, dans lesquelles le support physique de culture est constitue de billes de verre, sont necessaires pour etudier certains processus physiologiques comme l'exsudation racinaire ou l'absorption minerale. Les effets de la contrainte mecanique induite par la presence des billes de verre sur l'evolution architecturale du systeme racinaire du mais jeune ont ete examines. Une reduction de la longueur de toutes les racines (nodales et seminales), une augmentation du diametre des racines seminales et une modification de la ramification racinaire d'ordre 2 ont ete observees. La biomasse racinaire n'est pas modifiee (a l'exception des plantes agees de 16 j), mais la surface racinaire totale est reduite. La croissance des parties aeriennes est significativement diminuee lors de l'application de la contrainte mecanique.