核磁共振技术在沼生栎种子失水过程中水分相态变化  

Changes of Water Phases during Desiccation of Quercus palustris seeds by Nuclear Magnetic Resonance

作　　者：袁鸣 朱铭玮 解志军 康真 张中会 李淑娴[1] Yuan Ming;Zhu Mingwei;Xie Zhijun;Kang Zhen;Zhang Zhonghui;Li Shuxian(Co-Innovation Center for the Sustainable Forestry in Southern China,Nanjing Forestry University,Nanjing 210037;Nanjing Government of the People’s Republic of China Hengliang Subdistrict Agricultural Service Center,Nanjing 211515;Xiangyang Forestry Science and Technology Promotion Station,Xiangyang 441022;Suzhou Newmine Analytical Instruments Co.,Ltd,Suzhou 215163)

机构地区：[1]南京林业大学南方现代林业协同创新中心,南京210037 [2]南京市六合区人民政府横梁街道农业服务中心,南京211515 [3]襄阳市林业科学技术推广站,襄阳441022 [4]苏州纽迈分析仪器股份有限公司,苏州215163

出　　处：《林业科学》2023年第11期42-48,共7页Scientia Silvae Sinicae

基　　金：江苏高校优势学科建设资助项目(PAPD)。

摘　　要：【目的】沼生栎以播种繁殖为主,但该种子对失水较敏感,具有顽拗性。本研究旨在探究沼生栎种子失水过程中水分相态的变化,探明半致死和致死含水量,为其运输、安全贮藏提供理论依据,也为其他顽拗性种子的研究提供参考。【方法】采用自然干燥法降低种子的含水量,利用核磁共振技术探求失水过程中种子内部水分相态、含量的变化,并结合种子发芽率的变化,分析各相态的水分在种子脱水中的作用。【结果】1)沼生栎种子初始含水量为38.0%,发芽率为96.00%。随着含水量的下降,种子发芽率不断下降,当含水量降至10.0%时,种子完全死亡。由拟合曲线计算得知种子的半致死含水量为17.39%。2)核磁共振波谱图表明,沼生栎种子水分质量(x)与核磁共振弛豫图谱峰面积(y)呈显著一元线性回归关系,其线性回归方程为:y=21132x+698.05,相关系数R^(2)=0.9996。3)T2弛豫图谱中各峰从左至右依次为:束缚水T_(21)、不易流动水T_(22)、自由水T_(23)。4)新鲜种子中自由水比例最高,占66.39%,而束缚水和不易流动水分别占4.28%、29.07%。失水过程中各相态水的结合能力、峰面积、峰比例也在不断变化。整个失水过程中束缚水性质稳定、不易脱除;不易流动水峰顶点整体向左偏移,结合能力增强;自由水流动性较强,峰顶点向右偏移。当含水量降至25.0%时,自由水峰面积显著下降,此时不易流动水和束缚水显著增加,比例也有所上升;当含水量继续降至20.0%时,束缚水峰面积及比例持续增大,不易流动水峰面积减小;随后各相态水峰面积均有所下降。【结论】随着失水时间的延长,沼生栎种子的发芽率不断降低,运输、贮藏过程中含水量不能低于其半致死含水量17.39%。失水过程中,沼生栎种子中始终存在束缚水、不易流动水、自由水3种相态的水分,且失水对沼生栎种子质量的影响很大,种子在受到失水胁【Objective】Quercus palustris is mainly propagated by seeds,but it is very difficult for seed storage due to its sensitiveness to the desiccation.This study aims to explore the changes of water phases during desiccation of Q.palustris seeds and find out the semi-lethal and lethal water contents,so as to provide a theoretical basis for scientific storage and transportation of seeds,and provide a new technique for the study of other recalcitrant seeds.【Method】The newly collected Q.palustris seeds were used as research materials in this study.The natural drying method was used to reduce moisture content of seeds.Nuclear Magnetic Resonance(NMR)technology was used to detect the changes of water phases and content in seeds during the desiccation process.Combined with the germination percentages of seeds under different water contents,the effects of water phases on seed dehydration were analyzed.【Result】1)The moisture content of fresh Q.palustris seeds was 38.0%,and the germination percentage was 96.00%.With the decrease of moisture content,the germination percentage decreased continuously.The seeds died completely when moisture content decreased to 10.0%.According to the fitting curve calculation,the semi-lethal moisture content was 17.39%.2)The NMR spectrum showed that there was a significant linear relationship between the water content(x)of Q.palustris seeds and the peak area(y)of the NMR relaxation spectrum,and the linear regression equation was:y=21132x+698.05,R^(2)=0.9996.3)From left to right,the peaks in T2 relaxation spectrum of transverse relaxation were bound water(T_(21)),immobile water(T_(22)),and free water(T_(23)).4)The proportion of free water in fresh Q.palustris seeds was the highest,accounting for 66.39%,while bound water and immobile water were 4.28%and 29.07%,respectively.In the process of desiccation,the binding capacity,peak area and peak proportion of water in each phase were in dynamic changes.During the desiccation process,the bound water was stable and hard to be removed.The peak ti

关 键 词：沼生栎 顽拗性种子 失水 核磁共振技术 

分 类 号：S792.18[农业科学—林木遗传育种]