Fig. 2.

Meristem identity genes in arabidopsis. (A) Inflorescence of the wild type (wt) and of lfy, ap1 and tfl1 mutants. In the inflorescences of lfy and ap1, flowers (open circles) are replaced by structures with shoot characteristics (indicated by arrowheads in the photographs), while in the tfl1 mutant solitary flowers replace shoots in the axils of cauline leaves (arrowheads). The inflorescences of the wild type, lfy and ap1 show indeterminate growth but the inflorescence of tfl1 is determinate and forms a terminal flower (arrow in the photograph). Filled circles in the diagrams represent abnormal flowers with shoot traits. (B) Complementary expression of TFL1 (blue) and LFY/AP1/CAL (red) genes in the arabidopsis inflorescence shoot apex. While LFY and AP1/CAL specify floral identity, TFL1 is required to maintain the inflorescence identity of all shoot meristems.