水稻光合关键酶类在光合日变化中的作用(英文)

Role of Key Enzymes for Photosynthesis in the Diurnal Changes of Photosynthetic Rate in Rice

研究了 2个水稻品种的剑叶净光合速率 ( Pn)、 Rubisco初始活力和 Rubisco活化酶活力、 Rubis-co活化酶含量和 ATP含量的日变化 ,以明确在体内 Rubisco活化酶是否对光合作用和 Rubisco活力的日变化起调节作用。结果表明 ,2个品种剑叶的 Pn、 Rubisco初始活力和 Rubisco活化酶活力在一天内变化较大 ,三者的日变化模式基本一致 ,即具有两个峰和一个低谷。Rubisco活化酶和 ATP的含量随时间推移而上升 ,下午明显高于上午。回归分析显示 ,无论在“午休”前、后或“午休”期间 ,Pn 极显著正相关与 Rubisco初始活力。这表明 Rubisco初始活力对光合日变化有很大的影响。Rubisco活化酶活力只有在“午休”前和“午休”后才分别与 Pn 和 Rubisco初始活力有显著正相关 ,“午休”期间无显著相关。说明光合“午休”涉及 Rubisco初始活力的下降 ,但“午休”前的光合上升和“午休”过后的光合再下降与 Rubisco和 Rubisco活化酶的活化和钝化有关。Rubisco活化酶活力与 ATP含量只有在午休前才有显著直线正相关 ,但全天中其含量与 ATP含量有显著指数正相关 ,表明体内超过一定范围的 ATP浓度可能参与

The diurnal variations of net photosynthetic rate (P n), activities of Rubisco and Rubisco activase (RCA) as well as RCA and ATP contents in flag leaves of two cultivars were measured to explore the possible effect of Rubisco activase in diurnal changes of P n and rubisco activation. The results showed that P n, initial Rubisco and RCA activities arose the typical pattern with two peaks in the morning and afternoon, respectively, and a midday depression at noon. However, RCA and ATP contents were markedly low in the morning than in the afternoon. Regression analysis indicated that P n was very significantly correlative to initial Rubisco activity during the day, but only correlated with RCA activity in the morning upon P n increasing and in the afternoon upon P n decreasing. It suggested that the midday depression of P n was involved in losing of the initial Rubisco activity. RCA activity correlated with ATP content only in early morning when ATP content was lower, but not at noon and in late afternoon when ATP content was higher. But RCA content increased slowly with increasing ATP content in early morning and did fast at noon and in the afternoon, implying that in vivo ATP might be involved in not only activation but also synthesis of RCA or/and protect the enzyme from degradation.