Acide, 2,3,5-triiodobenzoïque (TIBA) et initiation foliare chez Lycopersicon esculentum

Abstract

In Lycopersicon esculentum, treatment with 2,3,5-triiodobenzoic acid is followed by a stop in leaf initiation and the building of an aphyllous structure. However, the setting of provascular cells is maintained in this new structure, as well as the differentiation of the internal and external phloem, but xylem differentiation does not occur. Therefore, the differentiation of the provascular elements is independent of the localized phenomenon of leaf initiation. Only 10% of the treated plants recover their phyllotaxic activity after 2,3,5-triiodobenzoic is removed. The new leaves are formed following the spiral direction of the underlying foliar helices and the vessels differentiate only with the initiation of these new leaves. The first leaf newly erected is not in the extension of the underlying foliar helix on which it should be, but the recovery of the leaf initiation occurs in the next generative center. The new leaf always appears at the same place relative to the subjacent leaves, which supports the theory of an acropetal stimulus of leaf initiation.