key concept 37.2 Hormones and Signaling Determine the Transition from the Vegetative to the Reproductive State

Flowering is one of the major events in a plant’s life. Flowering requires a reallocation of energy and materials away from making more non-reproductive plant parts (vegetative growth) to making flowers and gametes (reproductive growth). Once a plant is old enough, it can respond to internal or external signals to initiate reproduction. Flowering can happen right at maturity as part of a predetermined developmental program or in response to environmental cues such as light or temperature.

focus your learning

  • Although in terms of flowering, many plants are classified as either short-day plants (SDPs) or long-day plants (LDPs), night length is actually the cue that controls flowering.

  • Receptors for the photoperiodic signal for flowering are located in the leaf, and a signal travels to the apical meristem.

  • The protein florigen converts a vegetative meristem into a reproductive meristem. Several genes are involved in the regulation and transport of florigen.

  • Temperature or gibberellin can induce flowering in some plants.