CHLOROPHYLL-A FLUORESCENCE TRANSIENT AS AN INDICATOR OF ACTIVE AND INACTIVE PHOTOSYSTEM-II IN THYLAKOID MEMBRANES
CHLOROPHYLL-A FLUORESCENCE TRANSIENT AS AN INDICATOR OF ACTIVE AND INACTIVE PHOTOSYSTEM-II IN THYLAKOID MEMBRANES
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DOI：
10.1016/0005-2728(90)90018-y
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发表时间：
1990-02-02
期刊：
影响因子：
--
通讯作者：
GOVINDJEE
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文献类型：
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作者：
CAO, J;GOVINDJEE
在光照下，暗适应的光合样品显示出叶绿素（Chl）荧光产量的时间依赖性变化，称为考茨基现象或OIDPS瞬态。基于电子受体如2，5-二甲基对苯醌（DMQ）和2，6-二氯对苯醌（DCBQ）对菠菜类囊体的Chl a荧光瞬变的差异效应，我们认为，在失活的PS II中，电子受体QA还原为Qa-（参见Graan，T.和Ort，D.（1986）Biochim. Biophys. Acta 852，320-330 [14]）。在菠菜类囊体中，热诱导的Chl a荧光产量的增加对DMQ和DCBQ的加入也是不同敏感的，这表明这种增加主要是在“I”水平上，因此建议加热将活性PS II转化为非活性PS II中心。从可变Chl a荧光计算的QA-的衰减动力学被分析为三个指数分量（365-395 μ s; 6-7 ms;和1.4-1.7 s）。在加热的样品中，可变叶绿素a荧光的衰减速率比正常的反反应速率慢，有一个优势的缓慢的组件，可能是由于，部分地，到非活性中心进行缓慢的反反应之间的QA-和S2状态的氧的演变复杂。
Upon illumination, a dark-adapted photosynthetic sample shows time-dependent changes in chlorophyll (Chl) a fluorescence yield, known as the Kautsky phenomenon or the OIDPS transient. Based on the differential effects of electron acceptors such as 2,5-dimethyl-p-benzoquinone (DMQ) and 2,6-dichloro-p-benzoquinone (DCBQ) on Chl a fluorescence transients of spinach thylakoids, we suggest that the OID phase reflects the reduction of the electron acceptor QA to Qa- in the inactive PS II (see Graan, T. and Ort, D. (1986) Biochim. Biophys. Acta 852, 320-330 [14]). In spinach thylakoids, heat-induced increase of the Chl a fluorescence yield is also differentially sensitive to the addition of DMQ and DCBQ suggesting that this increase is mainly on the ''I'' level, and thus heating is suggested to convert active PS II to inactive PS II centers. The kinetics of decay of QA-, calculated from variable Chl a fluorescence, was analyzed into three exponential components (365-395 .mu.s; 6-7 ms; and 1.4-1.7 s). In heated samples, the decay rate of variable Chl a fluorescence is slower than the normal back-reaction rate; there is a preponderance of the slow component that may be due, partly, to the inactive centers undergoing slow back reaction between QA- and the S2 state of the oxygen-evolving complex.