Figure 11.

Carpel development can occur independently of AG. (A) ap2-2-mutant flower. The first whorl carpels have all of the characteristics of carpels: ovules (o), stigmatic tissue (sg), style tissue (sy), valve cells (ow), and septum pri-mordia (sp). (B) The ap2-2 ag-1 first whorl carpels still retain many carpel specific tissues despite the absence of AG. Ovules and stigmatic tissue are clearly present, but the valve cells are absent. (C) The spt-2 ap2-2 pi-1 ag-1 quadruple-mutant flower shows a dramatic reduction in carpelloid properties of the outer whorl carpels. The stigma and style cells are completely absent. The only carpelloid tissue remaining is the ovule projections from the margins (arrows). The pi-1 mutation was included to remove the stamenoid organs still present in ap2-2 ag-1 mutants and does not affect the carpels of the first whorl. (D) The crc-1 spt-2 ap2-2 pi-1 ag-1 quintuple-mutant flower. Removal of CRC removes most of the rest of the carpel-loid properties of the outer whorl organs. (E) The ag ap2 shp1 shp2 quadruple-mutant flower. SHP acts partially redundantly with AG in the specification of carpels in the first whorl of ap2 mutants. Scale bars in A and B are 100 µm, C and D are 250 um, and E is 50 µm. A–D: from Alvarez and Smyth, 1999. E: From Pinyopich et al., 2003. Reproduced with permission from Nature Publishing Group (http://www.nature.com/).