Fig. 7. Flower structure of rbe-1 ap3-5 double mutant and in situ localization of RBE transcripts in floral mutants. (A-D) SEM images of ap3-5 (A,B) and the rbe-1 ap3-5 double mutant (C,D). (B) A high magnification image of the second whorl organ in A. The stomata and long cells characteristic of sepal epidermis are present. (C) Arrowheads indicate underdeveloped organs formed in the second whorl. (D) A high magnification image of the second whorl organ in C. Stomata and long cells are present. (E,F) AP3 expression patterns in a transverse section of a wild-type inflorescence (E) and a longitudinal section of a stage 3 flower (F). (G,H) The AP3 expression patterns in a transverse section of a rbe-1 inflorescence (G) and a longitudinal section of a stage 3 flower (H). (I,J) RBE expression patterns in continuous transverse sections of an ap3-5 inflorescence (arrowheads). (K,L) RBE expression analysis in longitudinal sections of the early (K) and late (L) stage 3 flowers of 35S::PI 35S::AP3. RBE is not expressed in the organ primordia of the outermost whorl (shown as p'), but is expressed in the precursor cells of the second whorl organ primordia (arrowhead in L). (M,N) RBE expression in transverse sections of ag-1. Arrowheads indicate RBE expression. Numerals in N indicate the whorl number where the organ primordia form. (O,P) RBE expression analysis in a longitudinal section of ap1-1 (O) and a transverse section of ptl (P). RBE expression is not detected in the region where petal primordia would be expected to form (arrowheads). Asterisks in E, G, I, J, M and P indicate the position of the inflorescence meristem. se, sepal primordia; p', petal primordia in the outermost whorl; st, stamen primordia; ca, carpel primordia. Scale bars: A, 500 µm; B,D,E-P, 50 µm; C, 200 µm.