ILLUMINATING FLOWERS - CONSTANS INDUCES LEAFY EXPRESSION

Higher plants must undergo a major developmental switch, the transitio n to flowering, if they are to successfully complete their life cycle. In many plants, the crucial decision of when to begin to produce flow ers is primarily controlled by environmental signals. The process of f loral induction involves the integration of the activities of two type s of genes: those that control flowering time as a response to the env ironment as well as an endogenous clock, and those that determine the floral identity of the cells. The first direct link between these two classes of genes has now been demonstrated((1)). Forced expression of CONSTANS, a flowering-time gene, promotes flowering through the transc riptional activation of LEAFY, a flower-meristem-identity gene.