Polygalacturonase involved in cell separation in the final stages of pod shatter, in anther dehiscence and in floral organ abscission. (1,4-alpha-D-galacturonosyl)n+m + H2O = (1,4-alpha-D-galacturonosyl)n + (1,4-alpha-D-galacturonosyl)m. Expressed in roots and in the abscission zone of the sepals, petals and stamens of flowers, at the base of cauline leaves and in the basal cell of trichomes from senescing leaves. Found at the site of lateral root emergence, in the dehiscence zone of anthers and maturing siliques. Also expressed early in anther development, at the time of microspore separation. Expressed in germinating seeds, at the point at which the radicle broke through the seed coat. Not expressed at the junction between the seed and the funiculus or in the dehiscence zone of anthers or pods. Up-regulated by ethylene. No visible phenotype under normal growth conditions. Small delay in floral organ shedding. Belongs to the glycosyl hydrolase 28 family.