Catalyzes the hydrolysis of phosphoanhydride bonds of nucleoside tri- and di-phosphates (By similarity). Involved in the regulation of pollen and anther development. a ribonucleoside 5'-triphosphate + 2 H2O = a ribonucleoside 5'-phosphate + 2 H(+) + 2 phosphate Detected in mature pollen grains. Also expressed in more diverse tissues such as roots, leaves, stems, pistils and sepals. More particularly expressed in the vascular bundle. By wounding and drought stress. No visible phenotype. Apy6 and dapy7 double mutant exhibits late anther dehiscence and low male fertility. Pollen grains of double mutant are largely deformed in shape and in most cases, the cell walls of the pollen grains are interconnected. Belongs to the GDA1/CD39 NTPase family. The predicted gene has been split into 2 genes: At4g19180 and At4g19185. The predicted gene has been split into 2 genes: At4g19180 and At4g19185.