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Redox changes of ferredoxin, P700, and plastocyanin measured simultaneously in intact leaves

Properties and performance of the recently introduced Dual/KLAS-NIR spectrophotometer for simultaneous measurements of ferredoxin (Fd), P700, and plastocyanin (PC) redox changes, together with whole leaf chlorophyll a (Chl) fluorescence (emission >760, 540 nm excitation) are outlined. Spectral in...

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Autor principal: Schreiber, Ulrich
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer Netherlands 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5683063/
https://www.ncbi.nlm.nih.gov/pubmed/28497192
http://dx.doi.org/10.1007/s11120-017-0394-7
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author Schreiber, Ulrich
author_facet Schreiber, Ulrich
author_sort Schreiber, Ulrich
collection PubMed
description Properties and performance of the recently introduced Dual/KLAS-NIR spectrophotometer for simultaneous measurements of ferredoxin (Fd), P700, and plastocyanin (PC) redox changes, together with whole leaf chlorophyll a (Chl) fluorescence (emission >760, 540 nm excitation) are outlined. Spectral information on in vivo Fd, P700, and PC in the near-infrared region (NIR, 780–1000 nm) is presented, on which the new approach is based. Examples of application focus on dark–light and light–dark transitions, where maximal redox changes of Fd occur. After dark-adaptation, Fd reduction induced by moderate light parallels the Kautsky effect of Chl fluorescence induction. Both signals are affected analogously by removal of O(2). A rapid type of Fd reoxidation, observed after a short pulse of light before light activation of linear electron transport (LET), is more pronounced in C4 compared to C3 leaves and interpreted to reflect cyclic PS I (CET). Light activation of LET, as assessed via the rate of Fd reoxidation after short light pulses, occurs at very low intensities and is slowly reversed (half-time ca. 20 min). Illumination with strong far-red light (FR, 740 nm) reveals two fractions of PS I, PS I (LET), and PS I (CET), differing in the rates of Fd reoxidation upon FR-off and the apparent equilibrium constants between P700 and PC. Parallel information on oxidation of Fd and reduction of P700 plus PC proves essential for identification of CET. Comparison of maize (C4) with sunflower and ivy (C3) responses leads to the conclusion that segregation of two types of PS I may not only exist in C4 (mesophyll and bundle sheath cells), but also in C3 photosynthesis (grana margins plus end membranes and stroma lamellae).
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spelling pubmed-56830632017-11-22 Redox changes of ferredoxin, P700, and plastocyanin measured simultaneously in intact leaves Schreiber, Ulrich Photosynth Res Original Article Properties and performance of the recently introduced Dual/KLAS-NIR spectrophotometer for simultaneous measurements of ferredoxin (Fd), P700, and plastocyanin (PC) redox changes, together with whole leaf chlorophyll a (Chl) fluorescence (emission >760, 540 nm excitation) are outlined. Spectral information on in vivo Fd, P700, and PC in the near-infrared region (NIR, 780–1000 nm) is presented, on which the new approach is based. Examples of application focus on dark–light and light–dark transitions, where maximal redox changes of Fd occur. After dark-adaptation, Fd reduction induced by moderate light parallels the Kautsky effect of Chl fluorescence induction. Both signals are affected analogously by removal of O(2). A rapid type of Fd reoxidation, observed after a short pulse of light before light activation of linear electron transport (LET), is more pronounced in C4 compared to C3 leaves and interpreted to reflect cyclic PS I (CET). Light activation of LET, as assessed via the rate of Fd reoxidation after short light pulses, occurs at very low intensities and is slowly reversed (half-time ca. 20 min). Illumination with strong far-red light (FR, 740 nm) reveals two fractions of PS I, PS I (LET), and PS I (CET), differing in the rates of Fd reoxidation upon FR-off and the apparent equilibrium constants between P700 and PC. Parallel information on oxidation of Fd and reduction of P700 plus PC proves essential for identification of CET. Comparison of maize (C4) with sunflower and ivy (C3) responses leads to the conclusion that segregation of two types of PS I may not only exist in C4 (mesophyll and bundle sheath cells), but also in C3 photosynthesis (grana margins plus end membranes and stroma lamellae). Springer Netherlands 2017-05-11 2017 /pmc/articles/PMC5683063/ /pubmed/28497192 http://dx.doi.org/10.1007/s11120-017-0394-7 Text en © The Author(s) 2017 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
spellingShingle Original Article
Schreiber, Ulrich
Redox changes of ferredoxin, P700, and plastocyanin measured simultaneously in intact leaves
title Redox changes of ferredoxin, P700, and plastocyanin measured simultaneously in intact leaves
title_full Redox changes of ferredoxin, P700, and plastocyanin measured simultaneously in intact leaves
title_fullStr Redox changes of ferredoxin, P700, and plastocyanin measured simultaneously in intact leaves
title_full_unstemmed Redox changes of ferredoxin, P700, and plastocyanin measured simultaneously in intact leaves
title_short Redox changes of ferredoxin, P700, and plastocyanin measured simultaneously in intact leaves
title_sort redox changes of ferredoxin, p700, and plastocyanin measured simultaneously in intact leaves
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5683063/
https://www.ncbi.nlm.nih.gov/pubmed/28497192
http://dx.doi.org/10.1007/s11120-017-0394-7
work_keys_str_mv AT schreiberulrich redoxchangesofferredoxinp700andplastocyaninmeasuredsimultaneouslyinintactleaves