Lehrstuhl Botanik I, Universität Würzburg, Mittlerer Dallenbergweg 64, D-8700, Wurzburg, FRG.
Photosynth Res. 1986 Jan;9(1-2):261-72. doi: 10.1007/BF00029749.
A newly developed modulation fluorometer is described which operates with 1 μsec light pulses from a light-emitting diode (LED) at 100 KHz. Special amplification circuits assure a highly selective recording of pulse fluorescence signals against a vast background of non-modulated light. The system tolerates ratios of up to 1:10(7) between measuring light and actinic light. Thus it is possible to measure the "dark fluorescence yield" and record the kinetics of light-induced changes. A high time resolution allows the recording of the rapid relaxation kinetic following a saturating single turnover flash. Examples of system performance are given. It is shown that following a flash the reoxidation kinetics of photosystem II acceptors are slowed down not only by the inhibitor DCMU, but by a number of other treatments as well. From a light intensity dependency of the induction kinetics the existence of two saturated intermediate levels (I1 and I2) is apparent, which indicates the removal of three distinct types of fluorescence quenching in the overall fluorescence rise from F0 to Fmax.
一种新开发的调制荧光计，采用发光二极管（LED）以 100 kHz 的频率发出 1 μsec 的光脉冲进行工作。特殊的放大电路确保了在高度调制光的背景下，对脉冲荧光信号进行高度选择性的记录。该系统可以容忍测量光与激活光之间高达 1:10(7)的比率。因此，可以测量“暗荧光产率”并记录光诱导变化的动力学。高时间分辨率允许记录饱和单转换闪光后的快速弛豫动力学。给出了系统性能的示例。结果表明，在闪光之后，光系统 II 受体的再氧化动力学不仅被抑制剂 DCMU 减缓，而且还被许多其他处理方法减缓。从光强依赖性诱导动力学可以看出，存在两个饱和中间水平（I1 和 I2），这表明在从 F0 到 Fmax 的整个荧光上升过程中，去除了三种不同类型的荧光猝灭。
