Superoxide dismutase, glutathione reductase and total glutathione in Pinus needles show similar seasonal changes with a maximum in winter and a minimum in summer. Drough does not change seasonal patterns of the activities of the antioxidative enzymes superoxide dismutase and glutathione reductase or the levels of the antioxidant glutathione in Pinus needles. The activity of superoxide dismutase, and glutathione reductase as well as glutathione level are higher in one-year-old needles than in young needles. GST activity showed inverse seasonal pattern to superoxide dismutase and glutathione reductase activities or glutathione levels with a maximum in summer. GST activity decreased with increase of needles age. GST activity shows a high gradient distribution in young needles during summer. Light or UV-B promote this gradient distribution of GST activity in young needles. Pinus GST are not involved in detoxification of lipid peroxidation products. GST activity does not respond to ozone fumigation, cold stress and senescence. GST activity may not directly correlate with the production of secondary phenolic compounds by phenylopropanoid pathway. Glutathione is stored in winter to support the new needle germination in the subsequent year with reduced sulfur, but also to provide enhanced antioxidative capacity for the Haliwell-Asada pathway.
