Fig. 4. Expression of AP1 RNA in sections of inflorescence apices of wild-type (A), strong LFY:VP16 (B), ag-1 (C), and strong LFY:VP16 ag-1 (E) plants (meristems indicated by asterisks). Numbers indicate floral stages (Smyth et al., 1990). (D,F) Sections of individual ag-1 (D) and LFY:VP16 ag-1 (F) flowers. In wild type AP1 is activated as soon as flowers arise and expressed throughout floral primordia until stage 2. In ag mutants, AP1 expression persists in the center of floral meristems (arrowhead in D). (E,F) In LFY:VP16 ag plants, AP1 RNA is eliminated from the center of floral meristem after only a few whorls of organs have formed (arrows). Note secondary flowers (sf) in F. The inset in F shows the central meristem in a fully reverted flower, with a pattern of AP1 expression similar to that of a wild-type inflorescence apex. Scale bar in F represents 50 µm for all panels, except for the inset in F (24 µm).