May be involved in the coordinated dissolution of the cell wall matrix during abscission and in the secondary cell wall formation in xylem vessels. Hydrolysis of terminal non-reducing alpha-L-arabinofuranoside residues in alpha-L-arabinosides. High expression in flowers, siliques and stems. Observed in the vasculature of older root tissue, at the tip of anthers and in the petal blade of fully developed flowers, in floral abscission zones and in silique replum tissue. Expressed in the cambium and phloem, but not in the xylem or in the vascular system of floral tissues. Not induced by hormones or during leaf senescence. No visible phenotype, even in asd1 and asd2 double mutant. Belongs to the glycosyl hydrolase 51 family.