Two fundamentally different types of variable chlorophyll fluorescence in vivo

被引:74
作者
Schreiber, U
Krieger, A
机构
[1] Lehrstuhl Botanik I, Julius-von-Sachs-Institut F. B., Universität Würzburg, D-97082 Würzburg
关键词
chlorophyll fluorescence; photosynthesis; photosystem II; reversible radical pair model; polyphasic fluorescence rise;
D O I
10.1016/S0014-5793(96)01176-3
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Upon onset of saturating continuous light only the first part of the observed polyphasic fluorescence rise follows Q(A) reduction (photochemical phase), whereas the remaining part (thermal phases) is kinetically limited by relatively slow reactions with light saturated half-times in the order of 10-50 ms. A simple hypothesis is presented for the interpretation of these fundamentally different types of variable fluorescence. The hypothesis, which is based on the reversible radical pair model of PSII, assumes stimulation of both prompt and recombination fluorescence upon Q(A) reduction, with only recombination fluorescence being in competition with nonradiative energy loss processes at the reaction centers. It is proposed that changes in the rate constants of these processes modulate the yield of recombination fluorescence in closed centers, thus causing large variations in the maximal fluorescence yield and also giving rise to the 'thermal phases'. This hypothesis can reconcile numerous experimental findings which so far have seemed difficult to interpret.
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页码:131 / 135
页数:5
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