Abstract: Four japonica rice varieties with significant differences in quality of eating and cooking were investigated to reveal the relationship between the key starch synthetic activities during grain filling and quality of eating and cooking of rice. The varieties presented the differences in amylose and amylopectin contents at the different grain filling stages. The differences were attributed to the various accumulation speed of starch during grain filling. The time when the enzyme activities reached a maximum for ADPglucose pyrophosphorylase (AGPP) and soluble starch synthesis (SSS) were not different in different quality types rice, but was different for starch branching enzyme (SBE), showed that the low quality varieties were earlier than that of the high quality ones, and high quality varieties still kept high enzyme activities at the late stages of grain filling. The correlation and correlative degree between AGPP, SSS, SBE and amylose content, amylopectin content, taste meter value, properties of amylogram varied with the different stage of grain filling. The correlation between soluble starch synthesis activity and taste meter value was not significant during the whole stage of grain filling, but at the early and late stage of grain filling, the activities of AGPP and SBE had significant or highly significant correlation with taste meter value. It is helpful for improving quality of eating and cooking of japonica rice by using the materials with low enzyme activity at the early stage or high enzyme activity at the late stage of grain filling as parents.

Key words: rice, grain filling, key enzymes for starch synthesis, rice quality

摘要： 选用稻米蒸煮食味品质有显著差异的4个粳稻品种，对水稻籽粒灌浆过程中淀粉合成关键酶的活性变化及其与蒸煮食味品质关系进行了研究。 不同品质类型的品种间籽粒直链淀粉和支链淀粉含量在灌浆前、中后期表现出差异，这种差异主要表现在灌浆不同时期淀粉积累速率上。籽粒灌浆过程中，不同品质类型的品种中ADPG焦磷酸化酶和可溶性淀粉合成酶活性出现峰值的时间无差异，但淀粉分支酶活性出现峰值的时间，劣质品种明显早于优质品种，而且优质品种灌浆中、后期仍然保持较高水平的酶活性。ADPG焦磷酸化酶、可溶性淀粉合成酶、淀粉分支酶的活性与直链淀粉含量、支链淀粉含量、味度值、RVA谱特性间的相关性和程度因灌浆时期不同而发生变化。在整个灌浆过程中，可溶性淀粉合成酶活性与味度值间的相关均不显著，但灌浆前期和中、后期的ADPG焦磷酸化酶和淀粉分支酶的活性与味度值间呈显著或极显著相关。选择灌浆前期酶活性低或灌浆后期酶活性高的材料，将有利于提高稻米蒸煮食味品质。

关键词: 水稻, 籽粒灌浆, 淀粉合成关键酶, 稻米品质