刺梨叶衰老过程中维生素C含量和部分抗氧化酶活性的变化

 以‘贵农5号’刺梨为试材, 研究了其叶片在自然衰老过程中部分相关生理指标的变化。结果表明, 随着叶片的逐渐衰老, 叶内O·2 产生速率、MDA含量、细胞质膜透性显著升高; 而光合色素、维生素C含量和POD、CAT活性则显著降低。可溶性蛋白质含量在衰老过程中的降解较为缓慢。其中O·2 产生速率与MDA含量和细胞质膜透性分别呈显著正相关, 而与维生素C含量则呈显著负相关。POD及CAT活性与细胞质膜透性间呈显著负相关关系, 说明两种酶在减缓叶片衰老过程中膜系统伤害方面具有重要作用。

Ascorbate Contents and Activities of Some Antioxidant Enzymes during Senescence of Rosa roxburghii Leaves

Rosa roxburghii Tratt‘Guinong 5’was used to investigate changes in ascorbate content and activities of some antioxidant enzymes in leaves during senescence. The results showed that O·2 generation rate, MDA content and plasma membrane permeability increased, while photosynthetic p igment and ascorbate content, POD and CAT activities decreased, significantly, together with a slow decrease in soluble protein content, with a p rogress in the leaf senescence. The change of O·2 generation rate was correlated significantly and positively withMDA content and p lasma membrane permeability, but significantly and negatively correlated with ascorbate content. The significantly negative correlation between the POD and CAT activities and the plasma membrane permeability suggests that the two enzymes played important roles in alleviating membrane damage caused by senescence.