Characterisation of germinating and non-germinating wheat seeds by nuclear magnetic resonance (NMR) spectroscopy
Characterisation of germinating and non-germinating wheat seeds by nuclear magnetic resonance (NMR) spectroscopy
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通过核磁共振 (NMR) 光谱表征发芽和非发芽小麦种子
DOI：
10.1007/s00249-003-0340-9
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
A. Moharir
中科院分区：
文献类型：
--
作者：
P. Krishnan;D. K. Joshi;S. Nagarajan;A. Moharir
进行实验以通过核磁共振（NMR）光谱来表征发芽和非发芽小麦种子中水分状态的变化。核磁共振弛豫时间 (T2) 测量显示不同水合阶段的三相或双相特征，具体取决于种子的发芽能力。 T2 数据的成分分析表明，干燥种子中仅存在两种成分：结合水和本体水。相比之下，发芽和非发芽小麦种子在水合第一阶段都具有三组分水质子系统（结合水、本体水和游离水）。在水合作用的滞后阶段（第二阶段），未发芽种子的大量水成分完全消失，形成双成分水质子系统。尽管如此，在第二阶段的发芽种子中观察到了三组分水质子系统。第二阶段之后，仅在发芽种子中观察到快速水合作用（第三阶段）。水质子重新组织，体积水和自由水增加，但结合水随之减少。通过核磁共振波谱法与组织浸出液电导率测量对这些种子中水的物理状态进行比较表明，种子膜系统在未发芽的种子中受到更明显的影响，导致细胞结构紊乱。本研究提供的证据表明，发芽小麦种子在水合过程中水的物理状态的重组对于其随后的发芽事件至关重要。
Experiments were conducted to characterise the changes, especially of water status in germinating and non-germinating wheat seeds by nuclear magnetic resonance (NMR) spectroscopy. NMR relaxation time (T2) measurements showed tri-phasic or bi-phasic characteristics during different stages of hydration, depending on the seed's ability to germinate. Component analysis ofT2data revealed the existence of only two components, bound and bulk water, in dry seeds. In contrast, both the germinating and non-germinating wheat seeds had a three-component water proton system (bound, bulk and free water) in phase I of hydration. During the lag phase (phase II) of hydration, bulk water component of non-germinating seeds disappeared completely, resulting in a two component water proton system. Nevertheless, the three component water proton system was observed in the germinating seeds in phase II. Following phase II, rapid hydration (phase III) was observed in germinating seeds only. Water protons were re-organised and there were increases in bulk and free water but decreases in bound water concomitantly. Comparison of the physical state of water in these seeds by NMR spectroscopy with that of tissue leachate conductivity measurement suggests that the seed membrane system was affected more evidently in non-germinating seeds, leading to the disorganised cell structure. The present study provides evidence that the reorganisation of physical state of water in germinating wheat seeds during hydration is essential for its subsequent event of germination.