Actin-depolymerizing protein. Severs actin filaments (F-actin) and binds to actin monomers. Binds monomeric actin (G-actin) with a marked preference for the ADP-loaded form and inhibits the rate of nucleotide exchange on G-actin. Required for pollen tube growth. Promotes turnover of longitudinal actin cables by severing actin filaments in pollen tubes. In germinating pollen grains and elongating pollen tubes, associates with the subapical actin fringe (PubMed:21632657). Associates with actin cables in the shanks of pollen tubes (PubMed:24058157). Specifically expressed in pollen. During male gametophyte development, expressed at the early microspore stage just after tetrad separation, polarized microspore stage, bicellular stage, mature pollen stage, anthesis stage and open flower stage. Expressed in germinating pollen grains and elongating pollen tubes. Decreased actin filament severing frequency. Increased amount of filamentous actin and inhibition of pollen tube growth. Belongs to the actin-binding proteins ADF family.