The Vernalization Pathway of Floral Induction and the Role of Gibberellin

Abstract Temperature, and particularly vernalization, exposure to a prolonged period of cold, is used by plants to regulate the onset of flowering. This is a sensible adaptation of plants in temperate climates to prevent the risk of autumn germination leading to flowering in winter, a time when pollinators are scarce and freezing temperatures may inhibit seed production. At the same time, the plant growth regulator gibberellin has been shown to be a powerful promoter of flowering in many species. For some time, there was speculation that the vernalization-induced flower induction pathway operated through gibberellins, but we now know, in Arabidopsis at least, that vernalization and gibberellin represent two independent pathways which can both induce flowering. This chapter considers the two pathways separately, before looking at the evidence that they overlap.