Original paper

Developmental conditions for terminal flower production in apioid umbellets

Bull-Hereñu, Kester; Claßen-Bockhoff, Regine


Quantitative ontogenetic studies in Daucus carota inflorescences illustrate that terminal flower producing umbellets ('closed' umbellets) have larger apical meristems than umbellets that lack terminal flowers ('open' umbellets). This structural difference is achieved through ontogeny by a different shaping of the apical meristem: in open umbellets it remains flat until it is completely consumed by flower primordia fractionation, while it becomes dome shaped in the closed umbellets. The convex meristem is finally transformed into a terminal flower that is larger than its direct neighbours. Since weaker and smaller individuals use to bear open umbellets, it is assumed that the relative nourishment conditions of the plants have an effect on the apical meristems geometry, that in turn would be capable or not to merge into a terminal flower.


apical meristeminflorescencemeristem fractionationmeristem shapingstructural determinism