Transcription activator that recognizes and binds to the DNA consensus sequence 5'-CAC[AG]N[AT]TNCCNANG-3'. Required for the initiation and growth of ovules integumenta, and for the development of female gametophyte. Plays a critical role in the development of gynoecium marginal tissues (e.g. stigma, style and septa), and in the fusion of carpels and of medial ridges leading to ovule primordia. Also involved in organs initiation and development, including floral organs. Maintains the meristematic competence of cells and consequently sustains expression of cell cycle regulators during organogenesis, thus controlling the final size of each organ by controlling their cell number. Regulates INO autoinduction and expression pattern. As ANT promotes petal cell identity and mediates down-regulation of AG in flower whorl 2, it functions as a class A homeotic gene