Analysis of Ascorbate Metabolism in Arabidopsis Under High-Light Stress.

Ascorbate is the most abundant soluble antioxidant in plants, and its concentration is enhanced under high-light and other abiotic stresses. One of the main functions of ascorbate is the detoxification of reactive oxygen species, as ascorbate-deficient plants are highly sensitive to high-light-induced photooxidative stress. Its antioxidative role in plants is further complemented by the presence of ascorbate peroxidases, as well as enzymes that recycle ascorbate from its oxidized forms. In parallel with ascorbate biosynthesis, the expression and activity of these enzymes are enhanced by photooxidative stress. Thus, ascorbate metabolism plays a key role in photooxidative stress acclimation. Herein, the present authors' preferred protocols for the application of high-light stress and the measurement of ascorbate and the activity of related enzymes are described.