灌浆结实期弱光对水稻籽粒蔗糖及其降解酶活性的影响

选用IR72（籼稻）和日本睛（粳稻），在开花后遮光处理，对弱光条件下籽粒蔗糖含量的动态变化和降解酶的活性进行了研究。结果表明：两品种籽粒的蔗糖含量减少，蔗糖分解加快，蔗糖合成酶（SS）活性下降，液泡型转化酶（VCI）和细胞壁结合型转化酶（WCI）活性提高。即在弱光条件下，转化酶活性的提高加快了蔗糖的分解。相关分析表明，蔗糖合成酶活性、细胞壁结合型转化酶活性与淀粉积累速率显著正相关。说明这两种酶在蔗糖的分解和淀粉的合成过程中起着十分重要的作用。

Effects of Weak Light on Rice Sucrose Content and Sucrose Degradation Enzyme Activities at Grain-Filling Stage

Two cultivars IR72(Indica) and Nipponbare(Japonica) were used with shading treatment after anthesis to study the dynamic changes of sucrose content and the activity of sucrose degradation enzymes.The results showed that sucrose contents were decreased,sucrose degradation accelerated,sucrose synthase(SS) activity was decreased and both vacuolar invertase(VCI) and cell wall bound invertase(CWI) activities were increased under the weak light.The shading treatment was favorable to sucrose degradation by increasing invertase activity.Correlation analysis showed that starch filling rate in grains was positively and significantly correlated with sucrose synthase activity and cell wall bound invertase activity,which played an important role in sucrose degradation and starch synthesis.