水稻灌浆期籽粒中淀粉合成关键酶的活性变化及其与灌浆速率和蒸煮品质的关系

Changes in Activities of the Key Enzymes Related to Starch Synthesis in Rice Grains During Grain Filling and Their Relationships with the Filling Rate and Cooking Quality

以10个水稻品种(系)为材料,研究了灌浆期籽粒中腺苷二磷酸葡萄糖焦磷酸化酶(ADPGPase)、淀粉合成酶(SSase)和淀粉分支酶(Q-酶)活性变化及其与灌浆速率、胶稠度(GC)、碱化值(ASV)和直链淀粉含量(AC)的关系。结果表明,籽粒中ADPGPase、SSase和Q-酶活性变化呈单峰曲线,前两个酶活性峰值出现的时间在最大灌浆速率的时间(Tmax)之前,Q-酶活性峰值的时间与Tmax趋于同步。上述各酶在灌浆前期的活性、灌浆期的最大活性和平均活性与平均灌浆速率、最大灌浆速率和籽粒中淀粉的含量(mg·粒-1)均呈显著或极显著正相关。灌浆各期籽粒中ADPGPase活性以及灌浆前、中期的Q-酶活性与蒸煮品质(GC,ASV和AC)的相关均不显著;灌浆前期SSase活性与GC和ASV呈显著负相关,与AC呈显著正相关,灌浆中期和后期的SSase活性以及灌浆后期的Q-酶活性与GC和ASV呈显著正相关,与AC呈显著负相关。灌浆前期喷施玉米素或脱落酸对籽粒中的ADPGPase、SSase和Q-酶活性有明显的调控作用。

With 10 rice cultivars (lines) as materials, the changes in activities of adenosine diphosphoglucose pyrophosphorylase (ADPGPase), starch synthase (SSase) and starch branching enzyme (Q-enzyme) in grains during filling period and their relationships with the filling rate, gel consistency (GC), alkali spreading value (ASV) and amylose content (AC) were studied. The results showed that changes in activities of ADPGPase, SSase and Q-enzyme exhibited a single peak during filling period, and the time of the activity peaks for the former two enzymes was earlier than that of the maximum grain-filling rate (Tmax), and the time reaching the peak for Q-enzyme was synchronous with T . The activities at early grain filling stage, and the mean and maximum activities of each enzyme during grain filling period were positively and significantly or very significantly correlated with the mean and maximum grain filling rate and starch content (mg·grain-1) in grains. Activities of ADPGPase at all grain filling stages and those of Q-enzyme at the early and mid filling stages were not significantly correlated with the cooking quality (GC, ASV and AC). SSase activities at the early filling stage were significantly and negatively correlated with GC and ASV, and positively correlated with AC. Activities of SSase at mid and late grain filling stages and Q-enzyme at the late filling stage were significantly and positively correlated with GC and ASV, and negatively correlated with AC. Spraying zeatin or abscisic acid at early grain filling stage could obviously regulate the activities of ADPGPase, SSase and Q-enzyme in grains.