Flowering at the phytomer scale

Phytomers are the repetitive units of the shoot, produced by apical meristems. Their formation follows a stereotyped sequence that begins with the initiation of a leaf primordium, followed by an axillary meristem (AxM). This coordination is altered at the transition to flowering, after which newly formed phytomers display structural rearrangements caused by the repression of leaf growth and the acceleration of AxM development. These changes are discussed with the aim of integrating knowledge of floral transition into the molecular mechanisms of phytomer formation in arabidopsis. Special attention is paid to the role of the floral repressor TERMINAL FLOWER 1 in the last pretransition phytomers and to the action of LEAFY in the initiation of floral phytomers.