Antioxidant role of glutathione associated with accelerated aging and hydration of triploid watermelon seeds

Hydration offers an effective means for raising seed performance in many crop species. The objective of the present study was to evaluate the effect of hydration in vermiculite on germinability and antioxidant capacity of glutathione in artificially aged triploid seeds of two watermelon cultivars. Aging was achieved by incubating the seeds at 45°C and 79% relative humidity for 6 days and then air-drying them to their original moisture level (4%). Hydration was achieved by mixing untreated and aged seeds with moist vermiculite No. 3 at 25°C for 24 h. The partially hydrated seeds were air-dried at 25°C for 36 h to 4.7% moisture level. Aged seeds germinated more slowly and poorly than unaged seeds. Aging also decreased the level of glutathione and reduced the activity of several enzymes involved in glutathione antiperoxidation. The germinability of aged triploid seeds was restored partially by hydration in vermiculite. The glutathione content and the activity of antiperoxidative enzymes using glutathione as substrate were also increased by hydration. The changes in germination and glutathione level in relation to aging and hydration were similar for the two cultivars, despite differences in their germination performance and related physiological traits.