An improved method, using saturating light pulses, for the determination of photosystem I quantum yield via P700+-absorbance changes at 830 nm
An improved method, using saturating light pulses, for the determination of photosystem I quantum yield via P700+-absorbance changes at 830 nm
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DOI：
10.1007/bf00194461
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发表时间：
1994
期刊：
影响因子：
4.3
通讯作者：
C. Klughammer;U. Schreiber
中科院分区：
文献类型：
--
作者：
C. Klughammer;U. Schreiber
介绍了一种改进的光系统I量子产率测定方法。新方法采用饱和光脉冲与陡峭的上升特性，区分，在给定的生理状态下，从中心与减少受体侧的开放受体侧的中心。后者对PSI量子产率（ΦI）没有贡献。P700的氧化通过快速调制技术使用830 nm附近的吸光度变化来测量。量子产率Φ I由在给定状态下施加饱和脉冲时吸光度变化的快速相位的幅度（ΔA; 830 nm）除以由远红背景照明的饱和脉冲诱导的最大ΔA（830 nm）计算。使用这种技术，即使在受体侧限制的条件下，例如在暗光诱导期期间或从气流中消除CO2之后，也可以确定Φ I。由此测定的Φ I值与由叶绿素荧光参数计算的PSII的量子产率（ΦII）的值显示出接近线性的关系。结论是，所提出的方法可以提供新的信息的PSI受体侧的活动，从而有助于分离受体侧限制的影响，从那些循环PSI，每当Φ II和P700-还原水平之间的非线性关系被观察到。
An improved method is introduced for the determination of the quantum yield of photosystem I. The new method employs saturating light pulses with steep rise characteristics to distinguish, in a given physiological state, centers with an open acceptor side from centers with a reduced acceptor side. The latter do not contribute to PSI quantum yield (ΦI). Oxidation of P700 is measured by a rapid modulation technique using the absorbance change around 830 nm. The quantum yield ΦIis calculated from the amplitude of the rapid phase of absorbance change (ΔA; 830 nm) upon application of a saturation pulse in a given state, divided by the maximal ΔA (830 nm) which is induced by a saturation pulse with far-red background illumination. Using this technique, ΦIcan be determined even under conditions of acceptor-side limitation, as for example in the course of a dark-light induction period or after elimination of CO2from the gas stream. Thus determined ΦIvalues display a close-to-linear relationship with those for the quantum yield of PSII (ΦII) calculated from chlorophyll fluorescence parameters. It is concluded that the proposed method may provide new information on the activity of the PSI acceptor side and thus help to separate the effects of acceptorside limitation from those of cyclic PSI, whenever a non-linear relationship between ΦIIand the P700-reduction level is observed.