Briantais J M, Vernotte C, Picaud M, Krause G H
Biochim Biophys Acta. 1979 Oct 10;548(1):128-38. doi: 10.1016/0005-2728(79)90193-2.
A detailed study of the photo-induced decline in chlorophyll a fluorescence intensity (Kautsky phenomenon) in coupled isolated chloroplasts from a high level (P) to a low stationary level (S) is presented. 1. A linear relationship between P leads to S quenching and intrathylakoid H+ concentration was found. When the light-induced proton gradient was abolished by uncoupling, the fluorescence emission at room temperature was lowered proportionally to increased H+ concentration in the medium. 2. Fluorescence spectra at -196 degrees C of samples frozen at the P and S states showed no significant differences in the Photosystem I/Photosystem II ratio of fluorescence emission. Furthermore, freezing to -196 degrees C reversed the P leads to S quenching. This indicates that the P leads to S quenching is not related to an increase of spillover of excitation energy from Photosystem II to Photosystem I. 3. When Mg2+ was added to thylakoids suspended in a medium free of divalent cations, the inhibition of spillover required lower Mg2+ concentrations (half saturation at 0.6 mM). Increased proton concentration in the medium also inhibited spillover. 4. The results are interpreted in terms of two sites of Mg2+ and H+ effects on excitation deactivation in Photosystem II. One site is located on the outer face of the thylakoid membrane; action of both Mg2+ and H+ at this side diminishes spillover. The second site is located on the inner face of the membrane; as Mg2+ is displaced there by protons, a non-photochemical quenching of Photosystem II fluorescence is induced, which is manifested by the P leads to S decline.
本文详细研究了偶联的离体叶绿体中叶绿素a荧光强度从高水平（P）到低稳态水平（S）的光诱导下降（考茨基现象）。1. 发现P到S的猝灭与类囊体腔内H⁺浓度之间存在线性关系。当通过解偶联消除光诱导的质子梯度时，室温下的荧光发射与介质中H⁺浓度的增加成比例降低。2. 在-196℃下冷冻于P态和S态的样品的荧光光谱显示，光系统I/光系统II荧光发射比率没有显著差异。此外，冷冻至-196℃可逆转P到S的猝灭。这表明P到S的猝灭与从光系统II到光系统I的激发能溢出增加无关。3. 当向悬浮在不含二价阳离子的介质中的类囊体添加Mg²⁺时，抑制溢出所需的Mg²⁺浓度较低（半饱和浓度为0.6 mM）。介质中质子浓度的增加也抑制溢出。4. 结果从Mg²⁺和H⁺对光系统II中激发失活的两个作用位点进行了解释。一个位点位于类囊体膜的外表面；Mg²⁺和H⁺在此处的作用都会减少溢出。第二个位点位于膜的内表面；由于质子在那里取代了Mg²⁺，诱导了光系统II荧光的非光化学猝灭，这表现为P到S的下降。
