Fig. 2. The fil yab3 double mutant has defects in valve margin patterning. (A) Expression of FIL detected by in situ hybridization in a stage-8 wild-type gynoecium. (B-H) The fil yab3 fruits develop a complex arrangement of valve margin tissues in which the apical regions lack valve margin, while the basal regions develop ectopic valve margin. (B) SEM of a whole fil yab3 fruit. Brackets mark regions that develop no visible valve margin (–vm) and that develop ectopic valve margin (++vm). The gynophore is also expanded in fil yab3 mutants. (C) SEM of the apical region of a fil yab3 fruit. Note the lack of creases that normally mark the location of the valve margin. (D,E) Phloroglucinol-stained cross sections of the apical region of a fil yab3 fruit in the replum/valve margin region (D), or valve (E) region. The fruit lack lignin in cells normally found at the valve margin and enb layer. (F) SEM of the basal region of a fil yab3 fruit. A large stripe of valve margin-like tissue (evm) is shown passing through the middle of a valve. (G,H) Phloroglucinol-stained cross sections of the basal region of a fil yab3 fruit in the replum/valve margin (G) and valve (H) regions showing the expansion of lignified layer tissues into the valves. r, replum; v, valve; st, style; –vm, loss of valve margin; ++vm, ectopic valve margin; evm, ectopic valve margin; gy, gynophore; EL, ectopic lignification. Scale bar: 50 µm (A,D,E,G,H), 1 mm (B), 200 µm (C), 100 µm (F).