Effects of molybdenum application on redox of ascorbic acid in Chinese cabbage (Brassica campestris L. ssp. pekinensis)

A pot trial was conducted to investigate the effects of molybdenum (Mo) on redox of ascorbic acid in Chinese cabbage (Brassica campestris L. ssp. pekinensis). Mo was applied at four rates: 0, 0.075, 0.15 and 0.30 mg/kg soil. The fresh weight, concentrations of total ascorbate, reduced ascorbate, dehydroascorbate, and activities of four key enzymes in redox of ascorbic acid were studied. The results showed that Mo applications (0–0.30 mg/kg) increased the fresh weight, concentrations of total ascorbate and reduced ascorbate in Chinese cabbage. The activities of ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR) increased due to Mo application. But the activity of ascorbate oxidase (AAO) decreased with increasing Mo application rates. It is hypothesized that Mo may promote the redox process and regeneration of ascorbic acid. It is concluded that Mo applications increased ascorbic acid concentration in Chinese cabbage.