Effects of temperature and light intensity on ascorbic acid content in cotyledons of Japanese radish

摘要

The relationship between L-ascorbic acid (AsA) content in cotyledons of Japanese radish and temperature or light intensity during growth was investigated. Japanese radish seedlings were grown in the dark at 15, 20, 25, 30, or 35 deg C. The maximum rate of hypocotyl elongation occurred at 25 deg C treatment compared with other temperature treatments. However, lower temperatures led to higher maximum content of AsA in cotyledons on a fresh weight basis. At temperatures below 30 deg C, AsA content in cotyledons increased rapidly, reaching a maximum 3-5 days after sowing and subsequently declined. Japanese radish seedlings were grown under various light intensity conditions at 25 deg C. Illumination led to increase of AsA content in cotyledons. A linear relationship was observed between the AsA content and the logarithms of light intensity.