Publications

Authors:

Finazzi, G; Johnson, Gn; Dall'Osto, Luca; Joliot, P; Wollman, Fa; Bassi, Roberto

Title:

A zeaxanthin-indipendent nonphotochemical quenching mechanism localized in the photosystem II core complex

Year:

2004

Type of item:

Articolo in Rivista

Tipologia ANVUR:

Articolo su rivista

Language:

Inglese

Referee:

Sì

Name of journal:

Proceedings of the National Academy of Sciences of the United States of America

ISSN of journal:

0027-8424

N° Volume:

101

Page numbers:

12375-12380

Keyword:

NPQ; zeaxanthin; reaction center; Lhc

Short description of contents:

Illumination of dark-adapted barley plants with low light transiently induced a large nonphotochemical quenching of chlorophyll fluorescence. This reaction was identified as a form of high-energy-state quenching. Its appearance was not accompanied by zeaxanthin synthesis but was associated with a reversible inactivation of a fraction of photosystem II (PSII) centers. Both the fluorescence quenching and PSII inactivation relaxed in parallel with the activation of the Calvin cycle. We interpret the induction of this phenomenon as due to the generation of a quenched state in the PSII core complex. This reaction is probably caused by the transient overacidification of the thylakoid lumen, whereas its dissipation results from the relaxation of both the pH gradient across the thylakoid membrane and redox pressure upon activation of carbon fixation. At saturating light intensities, inactivation of PSII was still observed at the onset of illumination, although its recovery did not result in dissipation of high-energy quenching, which presents typical characteristics of an antenna-associated quenching at steady state. Reaction-center quenching seems therefore to be a common transient feature during illumination, being replaced by other phenomena (photochemical or antenna quenching and photoinhibition), depending on the balance between light and carbon fixation fluxes.

Product ID:

24428

Handle IRIS:

11562/24428

Deposited On:

March 29, 2012

Last Modified:

November 15, 2022

Bibliographic citation:

Finazzi, G; Johnson, Gn; Dall'Osto, Luca; Joliot, P; Wollman, Fa; Bassi, Roberto, A zeaxanthin-indipendent nonphotochemical quenching mechanism localized in the photosystem II core complex «Proceedings of the National Academy of Sciences of the United States of America» , vol. 101 , 2004 , pp. 12375-12380

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