ABSTRACT Using two phase systems, plasma membrane (PM) of root cells was separated and purified from Malus xiaojinensis Cheng et Jiang, and iron (Fe)-reductase activities on PM analyzed, under conditions of both the normal Fe level (+Fe) and the Fe deficiency stress (−Fe) were compared. The results showed that FeCN-reductase on PM depended on NADH as the electron donor. The FeCN-reductase activity was 2.66 μmol L−1 mg−1 min−1 at +Fe, while the reductase activity was 4.92 μmol L−1 mg−1 min−1 at −Fe. Fe-EDTA-reductase could depend on either NADH or NADPH as the electron donor. There were no differences in Fe-EDTA-reductase activities on PM at either +Fe or −Fe, when the electron donor was NADPH. NADH being as the electron donor, however, the Fe-EDTA-reductase activity was 4.06 μmol L−1 mg−1 min−1 at −Fe, while the reductase activity was 2.73 μmol L−1 mg−1 min−1 at +Fe. Therefore, Fe3+ reduction on PM by Fe-reductase systems could be induced and also enhanced in M. xiaojinensis by Fe deficiency stress, which indicated that M. xiaojinensis had a stronger Fe deficiency stress response, and it was an Fe-efficient fruit genotype.