English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Paper describes principles and application of a novel routine that enables the quantitative analysis of the photochemical O-J phase of the variable fluorescence F v associated with the reversible photo-reduction of the secondary electron acceptor QA of photosystem II (PSII) in algae and intact leaves. The kinetic parameters that determine the variable fluorescence F (PP)(t) associated with the release of photochemical quenching are estimated from 10 µs time-resolved light-on and light-off responses of F v induced by two subsequent light pulses of 0.25 (default) and 1000 ms duration, respectively. Application of these pulses allows estimations of (i) the actual value of the rate constants k L and k AB of the light excitation (photoreduction of QA) and of the dark re-oxidation of photoreduced QA ([Formula: see text]), respectively, (ii) the actual maximal normalized variable fluorescence [nF v] associated with 100 % photoreduction of QA of open RCs, and (iii) the actual size β of RCs in which the re-oxidation of [Formula: see text] is largely suppressed (QB-nonreducing RC with k AB ~ 0). The rate constants of the dark reversion of Fv associated with the release of photo-electrochemical quenching F (PE) and photo-electric stimulation F (CET) in the successive J-I and I-P parts of the thermal phase are in the range of (100 ms)(-1) and (1 s)(-1), respectively. The kinetics of fluorescence changes during and after the I-P phase are given special attention in relation to the hypothesis on the involvement of a Δµ H+-dependent effect during this phase and thereafter. Paper closes with author's personal view on the demands that should be fulfilled for chlorophyll fluorescence methods being a correct and unchallenged signature of photosynthesis in algae and plants.

photosynthesis research

A simple routine for quantitative analysis of light and dark kinetics of photochemical and non-photochemical quenching of chlorophyll fluorescence in intact leaves