鈣對紫菜用甘籍在乾旱逆境下脂質過氧化及抗氧化酵素活性之影響

The Effect of Calcium on Lipid Peroxidation and Antioxidative Enzyme Activities of Sweet Potato (Ipomoea batatas (L.) Lam.) under Drought Stress

本文探討鈣對葉菜用甘藉在乾旱逆境下，脂質過氧化及抗氧化酵素活性之影響。羅菜種甘藉之脂質過氧化產物malondialdehyde（MDA）含量在乾旱逆境下沒有增加，而‘桃園二號‘之MDA含量於乾旱逆境下明顯增加。加鈣前處理可使桃圍二號之MDA含量下降可能與其超氧歧化酶（superoxide dismutase, SOD）及過氧化氫酶（catalase, CAT）酵素活性受到加鈣前處理之誘導，而與過氧化物之清除有關。相對的，蕹菜種之SOD及抗壞血酸過氧化酶（ascorbate peroxidase, APX）活性可因加鈣前處理而增加，怛其CAT酵素活性於加鈣處理後反而下降，因此SOD及APX於蕹菜種之乾旱逆境耐受性扮演重要角色。兩種葉菜用甘藉之乾旱逆境耐受性亦與還原態ascorbate的含量有關。

The effects of calcium on lipid peroxidationand peroxide scavenging enzyme activities of sweet potato under drought stress were investigated. The level of malondialdehyde (MDA) did not increase under drought conditions in Yongtsai sweet potato, but significantly elevated level of MDA in Taoyuan-2 was observed. Calcium pretreatment lowered the level of MDA in Taoyuan-2 and was probably due to the induction of superoxide dismutase (SOD) and catalase (CAT) enzyme activities and might have resulted in the removal of preoxide. In contrast, inductions of SOD and ascorbate peroxidase (APX) were observed for Yongtsai sweet potato under drought stress with calcium pretreatment. However, CAT enzyme activity reduced if calcium was supplemented. Therefore, SOD and APX enzyme activities play important roles in drought stress tolerace in Yongtsai sweet potato. The level of reduced ascorbate had close relationship with the drought tolerance capability of the two leafy vegetable sweet potatoes.