The rhizotron (10) has an inner wall (12) coaxial with an external wall (13) and defining a root propagation space (11) intended to receive a substrate along with the external wall. An upper part of a housing (45) supports a seed independently from presence of the substrate within the space. The housing is in communication with the space. A supply system supplies liquid e.g. water or nutritive solution, to the space. The space comprises a set of zones including a liquid storage zone and a root propagation zone. The inner wall consists of a material chosen from a polymeric natural or synthetic material. The internal wall consists of a material of metal. An independent claim is also included for a method for determining a phenotypic characteristic of roots of plants.La présente invention est relative à un rhizotron (10) comportant :- une paroi interne (12),- une paroi externe (13), définissant avec la paroi interne (12) un espace de propagation racinaire (11), destiné à recevoir un substrat,- au moins un logement (45) en partie supérieure pour supporter, indépendamment de la présence de substrat dans lespace de propagation racinaire (11), une semence, ce logement (45) communiquant avec lespace de propagation racinaire.
