Etude cinétique de quelques événements lies à une levée de dominance apicale par décapitation ou ablation de l'axe principal à différents niveaux chez la Tomate, Lycopersicum esculentum

Abstract

In intact tomato plants, axillary buds are completely inhibited by the main apex. A release from apical dominance is obtained by decapitation or excision of the main axis at different levels. These excisions lead to a wave of mitotic reactivation along the main stem which progresses in the basipetal way and is followed by an activation of axillary bud in the acropetal direction, from the base to the axillary bud apex. After release from apical dominance, axillary buds don't react equally. There is a basipetal gradient of their capacity of outgrowth. In the younger subapical axillary buds, mitotic reactivation is the first step observed (after 3 h); the cellular elongation occurs after 3–6 h, and foliar organogenesis begins only after 24 h. The basal axillary buds are reactivated much later. Adult leaves don't play any role on their axiliaries: the total defoliation of the plant does not lead to the outgrowth of all the axillary or cotyledonary buds.