施氮量对超级稻南粳9108产量、淀粉RVA谱特征值和理化特性的影响

为探明施氮量对水稻RVA谱特征值、稻米淀粉结构和理化特性的影响,以超级稻品种南粳9108为材料,在大田种植,设置3个施氮水平,分别为全生育期不施氮（N0）、施纯氮180kg/hm²（N180）和360kg/hm²（N360）,研究了淀粉结构和理化性质与RVA谱特征值的关系。结果表明,与N0相比,N180和N360处理下南粳9108的产量显著增加,氮肥利用率则逐渐降低。与N0相比,N180处理下南粳9108的崩解值、热浆黏度、峰值黏度、糊化温度和胶稠度提升,消减值和直链淀粉含量降低;提高了支链淀粉中短中链含量、淀粉的无序结构、溶解度和膨胀度,降低了糊化焓和结晶度。N360处理的结果与上述结果相反。相关性分析表明,支链淀粉短中链含量与崩解值、淀粉的无序结构、溶解度和膨胀度呈显著或极显著正相关,与糊化焓、结晶度和消减值呈显著或极显著负相关。综上可得,全生育期施纯氮180kg/hm²时南粳9108支链淀粉结构和淀粉理化性质得到改善,优化了RVA谱特征值,使蒸煮食味品质变优。

Effects of Nitrogen Application Rates on the Grain Yield,Starch RVA Profile Characteristics and Physicochemical Properties of Super Rice Nanjing 9108

In order to elucidate the effects of nitrogen application rates on rapid visco analyzer (RVA) profile characteristics of rice and the structure and physicochemical properties of rice starch, a super rice variety Nanjing 9108 was used and grown in the paddy field under three nitrogen application rates of 0 (N0), 180 (N180) and 360kg N/ha (N360). The relationships between structure and physicochemical properties of starch and eating quality were investigated. Results showed that grain yields of Nanjing 9108 were significantly increased under N180 and N360 treatments, whereas the result was reversed in nitrogen use efficiency in comparison to N0. Compared with the N0 treatment, the RVA profile characteristics of Nanjing 9108, breakdown value, hot paste viscosity, peak viscosity, pasing temperature and gel consistency were increased, while the setback value and amylose content were decreased, as well as the mid-short chain content of amylopectin, starch disordered structure, solubility and swelling degree were increased, the enthalpy value and crystallinity were decreased under N180 treatment, whereas the results were reversed in a high N application rate (N360). Correlation analysis showed that short-mid chain content of amylopectin was positively correlated with breakdown value, starch disordered structure, solubility and swelling degree (P < 0.05 or P < 0.01), whereas negatively correlated with enthalpy value, crystallinity and setback value (P < 0.05 or P < 0.01). The results suggested that the optimized amylopectin structure and starch physicochemical properties accounted for the better RVA profile characteristics of Nanjing 9108 under 180kg N/ha, which was conductive to a better cooking and eating quality.