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Updated: Jul 24, 2025

Evaluation of Photosynthetic Behaviors by Simultaneous Measurements of Leaf Reflectance and Chlorophyll Fluorescence Analyses
Published on: August 9, 2019
New foundations for the physical mechanism of variable chlorophyll a fluorescence. Quantum efficiency versus the
Győző Garab1,2, Melinda Magyar1, Gábor Sipka1
1Institute of Plant Biology, Biological Research Centre, Szeged, Hungary.
Abstract:
Photosystem II (PSII) uses solar energy to oxidize water and delivers electrons to fix CO2. Although the structure at atomic resolution and the basic photophysical and photochemical functions of PSII are well understood, many important questions remain. The activity of PSII in vitro and in vivo is routinely monitored by recording the induction kinetics of chlorophyll a fluorescence (ChlF). According to the 'mainstream' model, the rise from the minimum level (Fo) to the maximum (Fm) of ChlF of dark-adapted PSII reflects the closure of all functionally active reaction centers, and the Fv/Fm ratio is equated with the maximum photochemical quantum yield of PSII (where Fv=Fm-Fo). However, this model has never been free of controversies. Recent experimental data from a number of studies have confirmed that the first single-turnover saturating flash (STSF), which generates the closed state (PSIIC), produces F1
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