用低场核磁共振检测水稻浸种过程中种子水分的相态及分布特征  

Moisture phase state and distribution characteristics of seed during rice seed soaking process by low field nuclear magnetic resonance

作　　者：宋平[1,2,3,4] 徐静[1] 马贺男[5] 王成 杨涛[1] 高鹤 

机构地区：[1]沈阳农业大学信息与电气工程学院,沈阳110866 [2]国家农业智能装备工程技术研究中心,北京100097 [3]农业部农业信息技术重点实验室,北京100097 [4]农业智能装备技术北京市重点实验室,北京100097 [5]中国刑事警察学院网络犯罪侦查系,沈阳110854 [6]辽宁省林业技术推广站,沈阳110036

出　　处：《农业工程学报》2016年第6期204-210,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家高技术研究发展计划(863计划):作物生产智能监控关键技术与系统研究(2012AA10A503);国家重大科学仪器设备开发专项"便携式植物微观动态离子流检测设备研发与应用"(2011YQ080052);公益性行业(农业)科研专项"作物育种材料农艺性状信息高通量获取与辅助筛分技术"(201203026)

摘　　要：为研究水稻浸种过程中种子的水分相态及其分布特征,利用低场核磁共振快速、无损、准确的检测技术,通过硬脉冲回波序列CPMG(carr-purcell-meiboom-gill sequence)测量水稻种子横向弛豫时间T2,根据横向弛豫时间T2的差异区分种子内部的水分相态及其变化规律。试验结果表明:通过T2反演谱横向弛豫时间T2长短的差异,发现水稻浸种过程中种子内部水分存在结合水、自由水2种水分状态,同时可区分出内层水、中层水、外层水3种水分分层;二者均能通过回归方程合理的估测水稻在浸种过程中种子的吸水率情况;通过T2反演谱信号幅值大小的差异,发现水稻浸种过程中的种子总水含量不断上升,但由于判定依据及划分方式的不同,二者在水分的流动方式上略显差异。低场核磁共振技术对水稻浸种过程中种子内部的水分变化进行了直观的揭示,提供了一种高效的种子水分检测方法。Nuclear magnetic resonance（NMR） is a fast, nondestructive and accurate test technique, which can be used to study the phase and distribution characteristics of moisture in rice seed during the soaking process. In this paper, the transverse relaxation time T2 has been analyzed by Carr-Purcell-Mei boom-Gill（CPMG） pulse sequence. Thephase and change rules of moisture in rice seed are distinguished according to the different transverse relaxation time T2 in the T2 inversion spectrum. Samples of rice seed（variety was Shennong 9903）were obtained from Rice Research Institution,Shenyang Agricultural University in 2014. The mass of 10 seeds was determined as one sample with the total weight of0.251 g, and there were 120 samples that were used in the present paper. The central frequency and the width of pulse of the magnetic field were searched by free induction decay（FID） pulse sequence, and all test samples were put in the low field NMR instrument one by one. All the tests were conducted by 4 times. The initial moisture content of the seeds was analyzed by NMR and the average transverse relaxation time T2 of rice seed was determined by CPMG pulse sequence. Test samples after data acquisition were soaked in water; the soaking time was ranging from 1 to 6h under standard laboratory conditions（20 ℃）. After wiping the surface water of test samples with absorbent paper, the soaked samples were put in the NMR instrument again for data collection, and each test was repeated by 4 times. The spin echo signals collected by the repeated tests were valuated by the NMR inversion fitting software, and the average value of the inversion results was taken as the relaxation time and the signal amplitude of the sample. All the experimental data were statistically analyzed and expressed by mean ± standard deviation, and the results were analyzed by the regression analysis. The comparative dispersion of the data were obliterated according to the composition of the samples, the NMR equipment and the different measureme

关 键 词：作物 水分 核磁共振 低场核磁共振 弛豫时间 弛豫谱 自由水 结合水 

分 类 号：S351.51[农业科学—作物栽培与耕作技术]