硒萌爆對苦瓜種子抗氧化作用之影響

Abstract

中 文 摘 要 硒是穀胱過氧化(GPX)主要活化部位的組成物，硒的含量多寡可決定穀胱過氧化活性的高低；此一酵素是有效的抗氧化酵素，可保護種子免於氧化傷害。本試驗以特六號(Special Six)及月華(Moon Shine)兩品種苦瓜種子為材料，將種子分別給予固體萌爆及硒萌爆處理後，置室內陰乾至原重，藉由檢測各項生理特性，以探討種子品質與穀胱過氧化及其相關抗氧化機制間之關係，及硒萌爆處理是否能改善種子內穀胱之生理代謝，並從而提昇種子之品質。試驗結果顯示，未經處理種子之浸潤滲漏、總過氧化物含量、脂質過氧化物MDA 之含量皆高於經過萌爆處理的種子，尤其在20℃下更加明顯，因此導致種子發芽及出土率下降。而硒萌爆處理後之苦瓜種子，其穀胱還原、穀胱轉移、還原態穀胱、抗壞血酸過氧化、癒創木酚過氧化、超氧歧化、觸、抗壞血酸等之活性及含量皆獲得提昇；而種子內浸潤滲漏及氧化態穀胱含量均下降，發芽率及出土表現、整齊度均獲得改善。顯示以此萌爆處理方式，確能改善苦瓜種子品質，且此品質之改善可能與穀胱相關的抗氧化機制之改變有關。

Abstract Selenium, an essential trace element, is known to play a crucial role in antioxidation in biological organism. As an antioxidant, selenium stimulates the activity of glutathione peroxidase which is capable of scavenging hydroperoxides. When sodium selenite was used to priming the seeds of two bitter gourd (Momordica charantia L.) cultivars ( Special six, and Moon shine), glutathione peroxidase activity was increased during 25 ℃and 20 ℃ germination. Moreover, the primed bitter gourd seed also demonstrated the enhanced activities of glutathione S - transferase, glutathione reductase, ascorbate peroxidase, catalase, guaiacol peroxidase, superoxide dismutase at two different germination temperatures. The levels of oxidative glutathione, malondialdenhyde, total peroxide, imbibition leakage content were also reduced by the selenium priming. The selenium priming also promoted germinability and improved emergence uniformity. These observations provide evidence to support the idea that selenium participates in antioxidative responses and subsequently scavenges H2O2 which might be produced during germination of bitter gourd seeds.