Plant and Cell Physiology Advance Access originally published online on February 5, 2008
Plant and Cell Physiology 2008 49(3):488-492; doi:10.1093/pcp/pcn018
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Short Communication |
Mechanisms to Avoid Photoinhibition in a Desiccation-Tolerant Cyanobacterium, Nostoc commune
Department of Life Science, Graduate School of Life Science, University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo, 678-1297 Japan
*Corresponding author: E-mail, s710624jp{at}yahoo.co.jp; Fax, +81-791-58-0549.
| Abstract |
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A desiccation-tolerant cyanobacterium, Nostoc commune, shows unique responses to dehydration. These responses are: (i) loss of PSII activity in parallel with the loss of photosynthesis; (ii) loss of PSI activity; and (iii) dissipation of light energy absorbed by pigment–protein complexes. In this study, the deactivation of PSII is shown to be important in avoiding photoinhibition when the Calvin–Benson cycle is repressed by dehydration. Furthermore, our evidence suggests that dissipation of light energy absorbed by PSII blocks photoinhibition under strong light in dehydrated states.
Keywords: Cyanobacteria - Desiccation-induced non-photochemical quenching - Desiccation tolerance - Hypertonic treatment - Nostoc commune - Photoinhibition
Abbreviations: Fo and Fm, minimum and maximum levels of Chl fluorescence in dark-adapted samples; Fm ' and F, maximum and steady-state levels of Chl fluorescence in samples illuminated with actinic light; Fv, variable part of Chl fluorescence (Fv = Fm – Fo); IAC, iodoacetamide; QA, a primary quinone electron acceptor of PSII
(Received December 3, 2007; Accepted January 26, 2008)
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