MONITORING DYNAMIC STATE OF WATER IN PLANT TISSUES USING ^1H-NMR

^ h - nmr是一种非破坏性的方法，可用于研究体内水的动态状态。我们应用核磁共振纵向弛豫时间（T_1）的研究表明，尽管植物组织中的水分状态主要受组织含水量的影响，但T_1估计的细胞水分动态状态与组织含水量不一定相关。植物的T_1值在许多种类、组织和器官中都是不同的。此外，T_1对低温、高温、脱水和接种线虫等不同环境胁迫均有敏感反应。1)本研究主要研究了油菜（Pisum sativum, cv.）幼苗的潜在矮化。进展9)与T_1的关系，反映了水质子的运动自由。2)采用^1H-NMR成像和TNBT染色观察低温保存的郁金香球茎水分物理状态和代谢活性。在冷冻鳞片中观察到较强的游离水信号，而在非冷冻鳞片中记录到较弱的游离水信号。郁金香球茎的信号强度和核磁共振弛豫时间反映了冷藏和非冷藏球茎的水结合程度和代谢活性的差异。3)研究了松材线虫接种松材后的水分关系和组织学特征。因此，认识“细胞或组织中水分的动态状态”对于准确理解植物生理学的各个领域是非常重要的。

^1H-NMR is a non-destructive method that can be used to study the dynamic state of water in vivo. Our studies applying NMR longitudinal relaxation times (T_1) showed that although the state of water in plant tissues is primarily influenced by tissue water content, the dynamic state of cell water estimated by T_1 are not necessarily correlate with the tissues water contents. T_1 values in plants are various in many kinds of species, tissues, and organs. Also, T_1 responds sensitively on different kinds of environmental stresses such as chilling, heat, dehydration and inoculation with nematode. 1) This study focuses on the potential dwarfism in seeedlings of Pisum sativum (cv. Progress No.9) in relation to T_1 reflecting the motional freedom of water protons. 2) The physical state of water and metabolic activity in tulip bulbs held at low temperatures were observed using ^1H-NMR imaging and TNBT staining. A strong free water signal was observed in scales for chilled bulb, while a weak water signal was recorded in non-chilled bulb scales. Signal intensity and NMR relaxation time for tulip bulbs reflected differences in the degree of water binding and metabolic activity between chilled and non-chilled bulbs. 3) Water relations and histological features of pine wood inoculated with pine wood nematode was studied. Thus, it may be pointed out that the awareness of "the dynamic states of water in cells or tissues" is very important for the accurate understanding of all fields of plant physiology.