水稻灌浆成熟期籽粒谷氨酰胺合成酶活性变化及其与稻米品质关系的初步研究

Changes of Activity of Glutamine Synthetase During Grain Filling and Its Influence on Rice Grain Quality

选用稻米蒸煮食味品质有显著差异的4个粳稻品种，通过盆栽试验对水稻灌浆成熟期籽粒谷氨酰胺合成酶活性变化及其与稻米蒸煮食味品质关系进行了初步研究。结果表明，水稻灌浆过程中籽粒谷氨酰胺合成酶活性随灌浆进程逐渐增加，达到峰值后叉逐渐下降，呈单峰曲线变化;抽穗15d以前蛋白质含量高的品种谷氨酰胺合成酶活性大于蛋白质含量低的品种，而以后与之相反；灌浆前期，籽粒谷氨酰胺合成酶活性与味度值、最高黏度、崩解值间呈负相关，灌浆中、后期呈正相关。而与籽粒最终蛋白质含量和黏滞峰消减值在灌浆前期呈正相关，灌浆中、后期呈负相关，而且相关程度随灌浆时段而发生变化;抽穗后15～20d是籽粒谷氨酰胺合成酶活性与味度值、RVA谱特性间的相关性质发生变化的转折时期。

Four japonica rice varieties differed in cooking and eating quality were used in the pot experiment to study the activity of glutamine synthetase during grain filling in association with rice quality. The activity of glutamine synthetase gradually increased and then declined as a single peak curve with the process of grain filling. The 15th day after heading was a turning point, before which the enzymatic activities of inferior varieties with high protein content were higher than those of superior varieties with low protein content and after which they were reverse. The activity of glutamine synthetase was negatively correlative with taste meter value, peak viscosity and breakdown at the early stage of grain filling and positively correlative with them at the middle and later stages, moreover, they were positively correlative with protein content of rice grain and setback at the early stage and negatively correlative with them at the middle and later stages, and correlative degree varied with grain filling stage. The duration from 15 d to 20 d after heading was the breakthrough stage at which the correlative nature varied between the activity of glutamine synthetase in rice grain and taste meter value and RVA properties.