Chlorophyll a fluorescence: beyond the limits of the Q(A) model

Schansker, Gert and Tóth, Szilvia Zita and Holzwarth, Alfred R. and Garab, Győző (2014) Chlorophyll a fluorescence: beyond the limits of the Q(A) model. PHOTOSYNTHESIS RESEARCH, 120 (1-2). pp. 43-58. ISSN 0166-8595

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Chlorophyll a fluorescence is a non-invasive tool widely used in photosynthesis research. According to the dominant interpretation, based on the model proposed by Duysens and Sweers (1963, Special Issue of Plant and Cell Physiology, pp 353-372), the fluorescence changes reflect primarily changes in the redox state of Q(A), the primary quinone electron acceptor of photosystem II (PSII). While it is clearly successful in monitoring the photochemical activity of PSII, a number of important observations cannot be explained within the framework of this simple model. Alternative interpretations have been proposed but were not supported satisfactorily by experimental data. In this review we concentrate on the processes determining the fluorescence rise on a dark-to-light transition and critically analyze the experimental data and the existing models. Recent experiments have provided additional evidence for the involvement of a second process influencing the fluorescence rise once Q(A) is reduced. These observations are best explained by a light-induced conformational change, the focal point of our review. We also want to emphasize that-based on the presently available experimental findings-conclusions on alpha/-centers, PSII connectivity, and the assignment of F-V/F-M to the maximum PSII quantum yield may require critical re-evaluations. At the same time, it has to be emphasized that for a deeper understanding of the underlying physical mechanism(s) systematic studies on light-induced changes in the structure and reaction kinetics of the PSII reaction center are required.

Item Type: Article
Subjects: Q Science / természettudomány > QH Natural history / természetrajz > QH301 Biology / biológia
Depositing User: MTMT SWORD
Date Deposited: 08 Oct 2014 13:05
Last Modified: 13 Oct 2014 12:50

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