Does not display typical F-actin depolymerizing activity. Exhibits a high ability to stabilize and cross-link actin filaments. Functions as an actin bundling protein with the highest efficiency under acidic conditions (PubMed:21570971). May play a role in the modulation of levels of histone H3 lysine 4 trimethylation and H3 lysine 9 and 14 acetylation at the FLC locus (PubMed:18830798). By auxin, gibberellin, abscisic acid (ABA) and kinetin in roots. Developmental defects, reduced plant size, early flowering and decreased number of inflorescence secondary branches. Belongs to the actin-binding proteins ADF family.