Rijgersberg C P, Melis A, Amesz J, Swager J A
Ciba Found Symp. 1978(61):305-22. doi: 10.1002/9780470720431.ch16.
Fluorescence kinetics and emission spectra of pea and spinach chloroplasts were studied between 294 and 4.2 K. In the presence of MgCl2 the fluorescence-induction curves were sigmoidal between 294 and 180 K but they lost their inflection points at lower temperature. In the absence as well as in the presence of Mg2+ ions, analysis of the kinetics of the area over the induction curve revealed two different components, indicating the existence of two different types of reaction centres at all temperatures. The 'rate constants' for these centres were nearly independent of temperature between 294 and 200 K, but showed a sharp decrease on further cooling. Emission spectra at low temperature showed the previously observed bands at 685, 695 and 735 nm. All three bands showed a considerable increase on cooling between 180 and 4.2 K, but with different temperature-dependence. The amplitude of the 695 band became constant below about 50 K, whereas the 685 emission increased markedly in this region. The relative proportion of the socalled variable fluorescence was almost the same at 685 and 695 nm, both at 80 and at 5 K. The data are discussed in terms of changes of energy-transfer rates on cooling.
在294至4.2K的温度范围内，研究了豌豆和菠菜叶绿体的荧光动力学和发射光谱。在存在MgCl2的情况下，荧光诱导曲线在294至180K之间呈S形，但在较低温度下失去了拐点。在不存在和存在Mg2+离子的情况下，对诱导曲线上方区域的动力学分析揭示了两个不同的成分，表明在所有温度下都存在两种不同类型的反应中心。这些中心的“速率常数”在294至200K之间几乎与温度无关，但在进一步冷却时急剧下降。低温下的发射光谱显示出先前观察到的685、695和735nm的谱带。在180至4.2K的冷却过程中，所有三个谱带都有相当大的增加，但具有不同的温度依赖性。695谱带的幅度在约50K以下变得恒定，而685发射在该区域显著增加。在80K和5K时，所谓可变荧光在685和695nm处的相对比例几乎相同。根据冷却时能量转移速率的变化对数据进行了讨论。
