Abstract
We studied the regulation system of biosynthetic pathway of ascorbate (AsA) in Arabidopsis plants which were cultured for 2 weeks on the MS medium containing 3% Suc under normal conditions. When the plants were transferred to the dark for 48 h, the level of AsA decreased. However, the transfer of dark-adapted plants from the dark to the light for 48 h did not allow AsA to restore to the initial level. The DCMU treatment also decreased the AsA level under light conditions.
To investigate the effect of exogenous sugar on the AsA level, two-week-old plants were transferred to the MS medium in the absence of Suc in the dark for 48 h. As a result, the AsA level decreased. Interestingly, the AsA level was increased to the initial level by reillumination for 48 h. There was no difference in transcript levels of enzymes in the AsA biosynthesis between both conditions.
