Catalyzes the conversion of monodehydroascorbate to ascorbate, oxidizing NADH in the process. Ascorbate is a major antioxidant against reactive oxygen species (ROS) and nitric oxide (NO). H(+) + 2 monodehydro-L-ascorbate radical + NADH = 2 L-ascorbate + NAD(+) Expressed in anthers. Induced by cold stress (PubMed:16263700). Induced during senescence (PubMed:25546583). Belongs to the FAD-dependent oxidoreductase family.