1 當植物遭遇環境逆境時，它會促進活性氧的生成，處於逆境下的植物 能調適或增強其抗氧化防禦系統(包括抗氧化酵素及非酵素性抗氧 化物) 。本試驗主要是研究「桃園二號葉用甘藷」於鹽分逆境下，葉 片的抗氧化酵素及非酵素性抗氧化物之變化，並且研究此甘藷在鹽分 逆境下，其抗氧化解毒機制。結果顯示桃園二號葉用甘藷之抗氧化酵 素及非酵素性抗氧化物皆會受鹽分逆境影響，在鹽分(90~150mM 氯 化鈉) 處理後，抗氧化酵素例如superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase 和glutathione reductase 之活 性有增加的趨勢，非酵素性抗氧化物例如total ascorbate 和glutathione 之含量則有減少的趨勢，葉綠素相對量則減低，離子滲漏增加。低濃 度鹽分(30~90mM 氯化鈉) 處理時，脂質過氧化會有減少的趨勢， 但高濃度鹽分(120~150mM 氯化鈉) 處理時，卻會有增加的趨勢。本 試驗結果暗示甘藷在鹽分環壓之下有調適此逆境的能力，它可能牽涉 一些關鍵的酵素性和非酵素性抗氧化系統。 When plants encounter environmental stresses, it can promote a generation of reactive oxygen species. Plants under stresses could modify or increase antioxidative defense systems (include antioxidative enzymes and non-enzymatic antioxidants). Experiments were conducted mainly to study the changes of antioxidative enzymes and non-enzymatic antioxidants in sweet potato (Ipomoea batatas (L.) Lam.cv. Taoyuan 2) leaves under salt stress. An antioxidative detoxification mechanism in the sweet potato under salt stress is also investigated. Results showed that antioxidative enzymes and non-enzymatic antioxidants in Ipomoea batatas (L.) Lam.cv. Taoyuan 2 were affected by salt stress. The activities of antioxidative enzymes such as superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase and glutathione reductase tended to increase after salt (90~150mM sodium chloride) treatments. The contents of non-enzymatic antioxidants such as total ascorbate and glutathione tended to decrease. The chlorophyll relative contents also decreased. Electrolyte leakage increased. Lipid peroxidation tended to decrease with lower concentrations of salt (30~90mM sodium chloride) treatments, but tended to increase with higher concentrations of salt (120~150mM sodium chloride) treatments. Results suggest that sweet potato has an ability to respond to salt stress, they may relate to involve of several key enzymatic and non-enzymatic antioxidant systems.
