The role of hormones in shoot apical meristem function.

Plant organs are produced in meristems in a continuous and predictable but nevertheless flexible manner. Phytohormones and transcription factors cooperate to balance meristem maintenance and organ production. Recent research has provided clues to the mechanisms underlying this cooperation. KNOTTED1-like homeobox (KNOX) and WUSCHEL (WUS) transcription factors facilitate high cytokinin activity in the shoot apical meristem (SAM), whereas high gibberellin and auxin activities promote the initiation of lateral organs at specific sites in the SAM flanks.