摘要
【目的】基于低场核磁共振(LF-NMR)技术观察水稻抽穗到成熟过程中籽粒水分状态的变化,探讨淀粉、蛋白质的积累效应对前者的影响,为水稻品质形成规律提供数据参考。【方法】对抽穗后63 d内的"越光"有机稻间隔采样,测定籽粒的百粒重、硬度、水分含量、淀粉含量和蛋白质含量,比较水稻在抽穗后不同生长时期的整体品质变化,通过LF-NMR测定的横向弛豫参数定性和定量地分析籽粒中的水分动态,探讨水稻品质形成过程与水分状态的相关联系。【结果】在抽穗后7—14 d百粒重和淀粉含量增长速率最快,两者表现极显著正相关(P<0.01)。籽粒硬度分别与淀粉含量和蛋白质含量都极显著正相关(P<0.01),与水分含量极显著负相关(P<0.01)。水分含量在抽穗后7—56 d从57.16%呈指数型下降到22.39%。淀粉含量在抽穗后42 d内呈"S"型曲线增长至50.47 g/100 g湿基。蛋白质含量在抽穗后7—49 d线性地增长至峰值6.56 g/100 g湿基。总体而言,水稻籽粒在抽穗后49 d左右整体品质已经形成。LF-NMR反演图谱表明在抽穗后7 d内籽粒部分水分往高自由度方向移动。抽穗后7—21 d,反演曲线整体向左迁移,表征流动性最弱"结合水"的T2b峰出现,表征束缚水的T_(22)峰发生峰的分化现象。4种横向弛豫时间T_(2b)、T_(21)、T_(22)和T_(23)随生长时期而减小,水稻籽粒中的整体氢质子自由度在逐渐降低。抽穗后21 d左右,"结合水"的峰比例超过束缚水和自由水的峰比例总和。籽粒内的水分含量和横向弛豫参数(T_(2b)、T_(21)、T_(22)、T_(23)、A_(2b)、A_(22)和A_(23))都随生长时期极显著地变化(P<0.01),而且淀粉和蛋白质积累与前者变化具有极显著的相关性(P<0.01)。尤其是淀粉充实胚乳细胞,水分子被淀粉颗粒包围或与其中的亲水基团氢键作用,使得整体水分状态向"结合水"的方向迁移。基于对横向弛豫信号的主成分分析,发现抽�
【Objective】This paper is mainly to observe the changes of moisture state of grains during the growth process of rice after heading by LF-NMR, and investigate the effects of accumulation of starch and protein on the moisture state of kernels, which provides reference for formation regularity of rice qualities.【Method】The spikes of “Yueguang” organic rice were sampled at intervals for 63 days after heading （DAH）, The 100-grain weight, hardness, moisture content, starch content and protein content were measured, separately, which were used to compare the changes of whole qualities of grains at different growth periods of rice after heading. The transverse relaxation parameters determined by LF-NMR were adopted to qualitatively and quantitatively analyze the moisture dynamics of grains. What’s more, the internal relationships between the formation process of rice qualities and moisture state of grains were discussed.【Result】Both the 100-grain weight and starch content for “Yueguang” organic rice increased most quickly within 7-14 DAH, and they were highly significantly and positively correlated with each other （P〈0.01）. Hardness was highly significantly and positively correlated with starch content and protein content, respectively （P〈0.01）, and negatively correlated with moisture content （P〈0.01）. Within 7-56 DAH, moisture content exponentially declined from 57.16% to 22.39%. With showing an S-shaped growth curve, starch content increased to 50.47 g/100g wet-basis within 42 DAH. Protein content linearly increased to the peak value of 6.56 g/100g wet-basis within 7-49 DAH. On the whole, the whole qualities of rice grains had been formed within 49 DAH. The inversion spectrum of LF-NMR data showed that part of water in the grains moved towards the direction of high mobility within 7 DAH. Within 7-21 DAH, when inversion curves of LF-NMR data gradually moved towards the left, T2b peak representing for “bound water＂ with least mobility occurred, followed by the differentiati
作者
邵小龙
汪楠
时小转
沈飞
宋伟
张强
SHAO XiaoLong WANG Nan SHI XiaoZhuan SHEN Fei SONG Wei ZHANG Qiang(College of Food Science and Engineering, Nanjing University of Finance and Economics/The Jiangsu Province Center of Cooperative Innovation for Modern Grain Circulation and Security/Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing 210023, China Department of Biosystems Engineering, University of Manitoba, Winnipeg MB R3T 5V6, Canada)
出处
《中国农业科学》
CAS
CSCD
北大核心
2017年第2期240-249,共10页
Scientia Agricultura Sinica
基金
国家自然科学基金(31201443)
公益性行业(粮食)科研专项(201513002-05)
江苏高校优势学科建设工程资助项目(PAPD)
关键词
水稻
籽粒淀粉积累
水分状态
核磁共振
横向弛豫特性
主成分分析
rice
starch accumulation of grains
moisture state
nuclear magnetic resonance
transverse relaxation characteristics
principal component analysis
