Parcours des faisceaux dans la tige adulte de Bryone (Bryonia dioica) (Cucurbitacées)

Abstract

The growth of a young internode of Bryone stem stops whenever it is submitted to repeated rubbings. To assess if this is connected to the anatomy of the stem, the latter has been studied following dissection. Whatever their number, at each node two bundles end at the base of the leaf and six others form anastomoses. The vascularization of the tendril, of the lateral branch, and of the axis of the inflorescence is also described. The bundle course is not uniform and one can distinguish two different types. In the first type connections occur every two internodes. In the second type connections can be found every three internodes (10-bundle stem) or five internodes (14-bundle stem). The return of the bundles to the initial position is realised every seven nodes in stems having 10 bundles and every nine nodes in stems with 14 bundles. The number of bundles remains invariable in the same stem, but it varies in the different organs supported by the stem at the successive nodes. The growth inhibition at the node level is discussed in relation to the described anatomy. [Traduit par le journal]