Fig. 1. Scheme depicting the development of the shoot apical meristem (SAM) of rice. (A) Vegetative meristem. Leaf primordia emerge from the SAM in an alternate phyllotaxis. (B) Reproductive meristem at the stage of primary branch meristem (PBM) formation. PBMs emerge spirally from the SAM at 144° from the previous one. (C) PBM at the spikelet and secondary branch meristem (SBM) formation stage. Meristems emerge from the primary branches in two alternate rows. Upper meristems acquire lateral SM identity whereas lower meristems form SBMs. The PBM itself acquire terminal SM identity. (D) SM at floret formation stage. Rudimentary glumes, empty glumes, lemma and palea primordia emerge alternately from the SM. (E) Schematic representation of a mature rice spikelet. Floral organs (not represented) are enclosed by the lemma and palea. (F) Schematic representation of a mature rice inflorescence. lp, leaf primordium; pbm, primary branch meristem; tsm, terminal spikelet meristem; lsm, lateral spikelet meristem; sbm, spikelet branch meristem; org, outer rudimentary glume; irg, inner rudimentary glume; oeg, outer empty glume; ieg, inner empty glume; l, lemma; p, palea; ma, main axis; pb, primary branch; sb, secondary branch; ts, terminal spikelet; ls, lateral spikelet; dp, degenerate point.