In addition to polymerase activity, this DNA polymerase exhibits 5'-3' exonuclease activity (By similarity). May be required for DNA replication and accumulation in plastids. a 2'-deoxyribonucleoside 5'-triphosphate + DNA(n) = diphosphate + DNA(n+1) Inhibited by dideoxythymidine-triphosphate (ddTTP), but not by aphidicolin and N-ethylmaleimide. Expressed in shoot apical meristem, root apical meristem, leaf primordia and the marginal meristem. Belongs to the DNA polymerase type-A family. Truncated N-terminus.