Development of symmetry in plants

Plant development involves specification and elaboration of axes of asymmet ry. The apical-basal and inside-outside axes arise in embryogenesis, and ar e probably oriented maternally. They are maintained during growth post-germ ination and interact to establish novel axes of asymmetry in flowers and la teral organs (such as leaves). Whereas the genetic control of axis elaborat ion is now partially understood in embryos, floral meristems, and organs, t he underlying mechanisms of axis specification remain largely obscure. Less functionally significant aspects of plant asymmetry (e.g. the handedness o f spiral phyllotaxy) may originate in random events and therefore have no g enetic control.