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. 2006 Feb 22;4:e0075. doi: 10.1199/tab.0075

Figure 23.

Figure 23.

Loss of replum development in replumless mutants is restored by removal of valve margin identity. (A) SEM close up of the replum (bracketed r), valve margins (vm arrowhead), and edges of the valves (v) of a wild-type (Ler) stage 17 fruit. (B) Cross section of the replum (arrow), valve margins (arrowheads) and edges of the valves (v) of a wild-type (Ler) stage 17 fruit. The medial vascular bundle (vb) runs through the inner part of the replum. (C) In rpl mutants, the replum fails to differentiate (bracket) and in its place the cell take on the characteristics of the valve margin cells (arrowheads). (D) In rpl mutants, the outer cells of the replum region are small and similar to valve margin cells. However, the inner parts of the replum including the vascular bundle are present in rpl mutants. (E) Removal of SHP activity from rpl mutants in shp1 shp2 rpl triple mutants rescues replum development. (F) The cells in replum of shp1 shp2 rpl fruit appear similar to wild-type replum cells. (G) Cross section of a wild-type replum region stained with safranin O and alcian blue. The separation layer (SL arrowhead) stains light blue, which is distinct from the lignified layer (LL arrowhead) and replum (R arrow). (H)‘In a moderate allele rpl-1, the replum region is covered with light blue staining cells that appear similar to the separation layer. (I) Cross section of a wild-type replum region stained with lignin specific stain phloroglucinol. The lignified layers (LL arrowhead) of the valve margins stain. (J) In a strong allele rpl-3, the valve margin lignified layers can connect across the replum. (K) RPL::RPL-GUS is expressed (pink) in the replum of a cross section of the gynoecium at stage 6. (L) RPL::RPL-GUS continues to be expressed strongly in the replum of a cross section of a stage 12 gynoecium. (M) RPL::RPL-GUS expression pattern in the replum and style of a stage 12 gynoecium. Scale bars in A-F represent 20 µm, scale bars in G-J represent 25 µm, and scale bars in K-M represent 50 µm. A-M: Reprinted from Current Biology, 13, Roeder, A.H.K, Ferrándiz, C., and Yanofsky, M.F., The role of the REPLUMLESS homeodomain protein in patterning the Arabidopsis fruit, 1630–1635, Copyright (2003), with permission from Elsevier.