Comparison of antioxidant enzyme activities between Solanum tuberosum L. Cultivars Danshaku and Kitaakari during low-temperature storage.

We compared the antioxidant enzyme activities between Solanum tuberosum L. cultivars Kitaakari and "Danshaku" during storage at 1 degrees C and 20 degrees C. The Kitaakari and Danshaku plants contained approximately 330 microM and 120 microM ascorbic acid (AsA) immediately after the harvest, respectively. At 1 degrees C, the activity of ascorbate peroxidase (APx) in the Kitaakari plants showed the tendency to increase, while in the Danshaku its activity increased temporally by 9 weeks and thereafter returned to basal levels. Superoxide dismutase (SOD) activity increased after 12 weeks in the case of the Kitaakari at 1 degrees C. Catalase did not show any difference in both cultivars at each temperature. The contents of AsA, which was one of the substrates of APx, decreased more rapidly at 1 degrees C than at 20 degrees C in both cultivars. Particularly in the case of the Danshaku, AsA contents were already less than 30 microM at 9 weeks, which confirmed that APx was inactivated.