花后弱光胁迫对成都平原籼稻米饭食味品质的影响

【目的】明确花后弱光胁迫对成都平原籼稻米饭食味品质的影响，为弱光稻区耐荫水稻品种的选用提供理论和实践依据。【方法】以不同直链淀粉含量籼稻品种为试验材料，于2019至2020年在四川温江开展田间控光试验，通过对稻米组分、RVA谱特征值，以及米饭质构特性和食味品质的测定，研究了弱光胁迫对水稻米饭食味品质的影响。【结果】（1）弱光胁迫显著降低稻米直链、支链和总淀粉含量，但显著提高蛋白质和脂肪含量。（2）弱光胁迫下，稻米峰值黏度和崩解值显著降低，糊化温度和消减值则显著增加。（3）弱光胁迫显著增加米饭硬度，降低黏度和弹性，使米饭外观和口感下降，综合评分显著降低。（4）主成分分析表明，稻米组分、RVA谱特征值和米饭质构特性可以解释81.2%的米饭食味品质变化。米饭综合评分与直链和总淀粉含量、峰值黏度、崩解值、弹性以及黏度呈显著正相关，与蛋白质和脂肪含量呈显著负相关。【结论】弱光胁迫下，蛋白质和脂肪含量对米饭食味品质的影响大于直链淀粉和总淀粉含量。弱光胁迫导致稻米淀粉、蛋白质和脂肪等组分发生显著变化，进而导致峰值黏度和崩解值下降，糊化温度和消减值升高，米饭变硬，黏度和弹性降低，最终使食味品质变差。

Effect of Post-Anthesis Shading Stress on Eating Quality of Indica Rice in Chengdu Plain

【Objective】 The aim of this study was to clarify the effect of post-anthesis shading stress on the eating quality of indica rice in Chengdu Plain, so as to provide the theoretical and practical basis for the selecting of shade-tolerant rice varieties in low light rice region. 【Method】 Field light control experiments were conducted in 2019 and 2020 in Wenjiang, Sichuan by using indica rice varieties with different amylose contents as materials. The effect of shading stress on eating quality of rice was studied by measuring the components and RVA spectrum values of rice, as well as the texture properties and eating quality of cooked rice. 【Result】(1)Shading stress significantly decreased amylose, amylopectin, and total starch contents of rice, but significantly increased the contents of protein and fat. (2)Shading stress significantly decreased the peak viscosity and breakdown of rice, while increased the pasting temperature and setback. (3)Shading stress also significantly increased the hardness of cooked rice, but decreased the stickiness and elasticity, which contributed to a significant reduction in the comprehensive score of cooked rice by decreasing both appearance and taste. (4)The results of principal component analysis showed that the rice components, RVA spectrum values, and texture properties could explain 81.2% of the total variation of eating quality of cooked rice. The comprehensive score of rice was significantly and positively correlated with the amylose, starch content, peak viscosity, breakdown, elasticity and stickiness, but negatively related to the protein and fat contents. 【Conclusion】 The protein and fat contents possessed greater influence on the eating quality of cooked rice than that of amylose and starch contents under shading stress. The shading stress leaded to significant variations in starch, protein, and fat components in rice, which contributed to a decrease in peak viscosity and breakdown, but an increase in pasting temperature and setback. And then, those variations contributed to the significantly decrease in eating quality of cooked rice by increasing the hardness, but decreasing both stickiness and elasticity of cooked rice.