Effect of UV-B radiation on GSH and GSH-related enzymes of brown alga Sargassum thunbergii (Mert.) O.Kuntze

The effect of UV-B radiation on activities of the glutathione reductase (GR), glutathione peroxidase (GPx), glutathione S-transferases (GST) and GSH content in Sargassum thunbergii, an intertidal macroalgae, were analyzed. While GR and GPx activities were relative stable in a low dosage of UV-B radiation (Luv), they decreased significantly under high dosage of UV-B radiation (Huv) with prolonged exposure. However, the activity of GST in Huv treatment did not decrease obviously in comparison with that of the control. GSH content increased rapidly under Luv and a medium dosage of UV-B radiation (Muv) with moderate exposure in the early stage. 11202 and TBARS accumulated rapidly, particularly for Muv and Huv treatments. These data indicate that S. thunbergii lacks tolerance to relatively higher dose of UV-B stress, although GSH-related enzymes may play certain role against UV-B induced oxidative damage.