Sane, Prafullachandra Vishnu ; Ivanov, Alexander G. ; Hurry, Vaughan ; Huner, Norman P. A. ; Öquist, Gunnar (2003) Changes in the redox potential of primary and secondary electron-accepting quinones in photosystem II confer increased resistance to photoinhibition in low-temperature-acclimated arabidopsis Plant Physiology, 132 (4). pp. 2144-2151. ISSN 0032-0889
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Official URL: http://www.plantphysiol.org/content/132/4/2144.sho...
Related URL: http://dx.doi.org/10.1104/pp.103.022939
Abstract
Exposure of control (non-hardened) Arabidopsis leaves for 2 h at high irradiance at 5°C resulted in a 55% decrease in photosystem II (PSII) photochemical efficiency as indicated by Fv/Fm. In contrast, cold-acclimated leaves exposed to the same conditions showed only a 22% decrease in Fv/Fm. Thermoluminescence was used to assess the possible role(s) of PSII recombination events in this differential resistance to photoinhibition. Thermoluminescence measurements of PSII revealed that S2QA- recombination was shifted to higher temperatures, whereas the characteristic temperature of the S2QB- recombination was shifted to lower temperatures in cold-acclimated plants. These shifts in recombination temperatures indicate higher activation energy for the S2QA- redox pair and lower activation energy for the S2QB- redox pair. This results in an increase in the free-energy gap between P680+QA- and P680+Pheo- and a narrowing of the free energy gap between primary and secondary electron-accepting quinones in PSII electron acceptors. We propose that these effects result in an increased population of reduced primary electron-accepting quinone in PSII, facilitating non-radiative P680+QA- radical pair recombination. Enhanced reaction center quenching was confirmed using in vivo chlorophyll fluorescence-quenching analysis. The enhanced dissipation of excess light energy within the reaction center of PSII, in part, accounts for the observed increase in resistance to high-light stress in cold-acclimated Arabidopsis plants.
Item Type: | Article |
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Source: | Copyright of this article belongs to American Society of Plant Biologists. |
ID Code: | 45106 |
Deposited On: | 25 Jun 2011 05:53 |
Last Modified: | 18 May 2016 01:29 |
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