Characteristic Changes in Relaxation Times of Water Protons in Vigna radiata Seedlings Exposed to Temperature Stress
Characteristic Changes in Relaxation Times of Water Protons in Vigna radiata Seedlings Exposed to Temperature Stress
复制标题
温度胁迫下绿豆幼苗水质子弛豫时间的特征变化
DOI：
10.1093/oxfordjournals.pcp.a078473
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发表时间：
1993
影响因子：
4.9
通讯作者：
S. Kaku
中科院分区：
文献类型：
--
作者：
M. Iwaya‐Inoue;K. Yoshimura;H. Yamasaki;S. Kaku
受到温度胁迫的绿豆黄化幼苗的下胚轴组织中的水质子在 1 H-NMR 中表现出特征性的弛豫行为。冷应力处理 (0°C) 导致 NMR 弛豫时间 (T1) 逐渐延长。组织暴露于冷应激24小时后，随后在常温（20℃）下孵育，T1恢复到初始值。相比之下，热应激处理 (40°C) 会导致 T1 随时间下降，在暴露于热应激 4 小时后在 20°C 下孵育后，T1 并未完全恢复到初始值。我们检查了影响T1对温度应激响应的各种物理因素的变化，即组织中的水分含量和蛋白质、抗磁性（K+、Na+、Ca2+和Mg2+）和顺磁性（Mn2+和Fe2+）离子的浓度。从体外T1与这些因素的关系来看，我们不能仅用含水量的变化来解释T1对温度胁迫的响应。 Mn2+-蛋白质复合物和 pH 值的协同效应可能对于冷应激引起的 T1 变化机制至关重要。从水-蛋白质相互作用的角度讨论热应激对组织中结构水的影响。
Water protons in hypocotyl tissues from etiolated seedlings ofVigna radiatathat were exposed to temperature stress showed characteristic relaxation behaviors for1H-NMR. Cold stress treatment (0°C) caused gradual prolongation of NMR relaxation times (T1). After exposure of tissues to cold stress for 24 h, T1returned to the initial value as a result of subsequent incubation at normal temperature (20°C). By contrast, heat stress treatment (40°C) induced a time-dependent decrease in T1, which did not return completely to the initial value upon subsequent incubation at 20°C after exposure to heat stress for 4 h. We examined changes in various physical factors that influence the response of T1to temperature stress, namely, water content and the concentrations of protein, diamagnetic (K+, Na+, Ca2+and Mg2+) and paramagnetic (Mn2+and Fe2+) ions in the tissues. From the relationships between T1and these factors in vitro, we could not interpret the responses of T1to the temperature stress only in terms of a change in water content. A synergistic effect of an Mn2+-protein complex and pH might be essential for the mechanism of changes in T1that are due to cold stress. The influence of heat stress on structural water in tissues is discussed in terms of water-protein interactions.