Un cas de ramification sympodiale à déterminisme endogène chez un système racinaire:Platanus hybridaBrot

Summary Morphological study of the Plane tree shows that the root system of this species has a completely sympodial structure. The layout of root sympodial units leads to a pseudomonopodial organization, never been observed in roots. The endogenous origin of this sympodial development is discussed. Abridged version Different works show us the occurence of sympodial branching in roots (Gill and Tomlinson, 1977; Oldeman, 1990). Usually, this type of branching is considered as a resuH of injury which accidentally destroy apical meristem (Wilson, 1970). Thus, analysis intended to understand structure and development of plane tree root system (Platanus hybrida Brat. Platanaceae) lead us to revise this interpretation. We made our observations in natural habHat near Montpellier in the South of France. We have completely freed root systems of thirty individuals from seedlings to aduHs developing Hs first main orthotropic branches. For each individual, we have described the morphology of each root taking in accoun...