Plays a key role in hydrogen peroxide removal (PubMed:15685422). Plays an important role in plant growth and development by protecting the seedlings from abiotic stresses through scavenging reactive oxygen species. Required for pollen viability (PubMed:23468992). H2O2 + L-ascorbate = 2 H2O + L-dehydroascorbate Binds 1 heme b (iron(II)-protoporphyrin IX) group. Inhibited by p-chloromercuriphenylsulfonic acid (CMPSA). Optimum pH is 6-7. Expressed in aerial vegetative parts and reproductive organs (PubMed:14644501). Expressed in roots, leaves, stems and flowers (PubMed:16397796). Expressed in young leaves, internodes, blade ears, stems and anthers (PubMed:23468992). By stress and hormones. By infection with rice blast fungus (M.grisea). Circadian-regulation. Expression is higher during the light phase than during the dark phase. Induced by salt stress (PubMed:16397796, PubMed:23468992). Induced by heat shock (PubMed:22196946). Induced by hydrogen peroxide in leaves (PubMed:25546583). Induced by drought and cold stresses (PubMed:23468992). Semi-dwarf plants, yellow-green leaves, leaf lesion mimic phenotype, abnormal anther morphology, defects in pollen viability and seed sterility. Binds one cation per subunit; probably K(+), but might also be Ca(2+) (By similarity). Plants over-expressing APX2 have increased ascorbate peroxidase activity and exhibit enhanced tolerance to salt, drought and cold stresses (PubMed:23468992). Belongs to the peroxidase family. Ascorbate peroxidase subfamily.