早晚季不同耐光氧化特性水稻品种籽粒灌浆关键酶活性变化

Changes of key enzyme activities in rice cultivars with different photooxidation-tolerance during grain-filling stage in early and late seasons.

选用光氧化敏感和不敏感的两大类型4个水稻品种研究早晚季耐光氧化反应特性与其稻米品质稳定性密切相关的生理生化原因.结果表明,耐光氧化反应特性强的适强光生态型水稻品种的平均灌浆速率(Gmean)、达最大灌浆速率时间(Tmax.G)和达最大灌浆速率百粒重(Wmax.G)等参数在早晚季灌浆结实期间保持相对稳定;而对光氧化敏感的弱光生态型品种佳禾早占以上参数的早晚季稳定性较差.比较早晚季籽粒灌浆充实过程中关键酶活性的变化结果可见,耐光氧化反应特性强的品种,灌浆速率高峰到灌浆终期ADPG-焦磷酸化酶和淀粉合成酶活性早晚季变异比耐光氧化反应特性弱的品种小,且耐光氧化反应特性强的品种灌浆高峰前后酶活性变异的幅度早晚季也较一致.

Four rice cultivars with different photooxidation-tolerance characteristics during grain-filling stage in early and late seasons were selected to uncover the physiological and biochemical mechanisms of the correlation between rice photooxidation.tolerance and grain quality. The results showed that the parameters mean grain-filling rate （Gmean）, time arrived to maximum grain-filling rate （Tmax. G）, and 100-grain weight at the maximum grain-filling rate （ Wmax.G） were relatively stable for the varieties adaptable to high light intensity, while on the contrary for those sensitive to photooxidation. The ADP glucose pyrophosphorylase and starch synthase activities of the varieties adaptable to high light intensity after grain-filling peaks had a less difference between early and late seasons than those sensitive to photooxidation, and the relative enzyme activities in the varieties adaptable to high light intensity changed coequally in early and late seasons.