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PHOTOPHYSIOLOGICAL PROPERTIES OF THE MARINE PICOEUKARYOTE PICOCHLORUM RCC 237 (TREBOUXIOPHYCEAE, CHLOROPHYTA)1
Article first published online: 13 MAR 2007
Journal of Phycology
Volume 43, Issue 2, pages 275–283, April 2007
How to Cite
Dimier, C., Corato, F., Saviello, G. and Brunet, C. (2007), PHOTOPHYSIOLOGICAL PROPERTIES OF THE MARINE PICOEUKARYOTE PICOCHLORUM RCC 237 (TREBOUXIOPHYCEAE, CHLOROPHYTA). Journal of Phycology, 43: 275–283. doi: 10.1111/j.1529-8817.2007.00327.x
1Received 27 April 2006. Accepted 6 December 2006.
- Issue published online: 13 MAR 2007
- Article first published online: 13 MAR 2007
- fluorescence quantum yield;
- nonphotochemical quenching of fluorescence;
- xanthophyll cycle;
The photophysiological properties of strain RCC 237 belonging to the marine picoplanktonic genus Picochlorum, first described by Henley et al., were investigated under different photon flux densities (PFD), ranging from 40 to 400 μmol photons· m−2·s−1, mainly focusing on the development of the xanthophyll cycle and its relationship with the nonphotochemical quenching of fluorescence (NPQ). The functioning of the xanthophyll cycle and its photoprotective role was investigated by applying a progressive increase of PFD and using dithiotreitol and norflurazon to block specific enzymatic reactions in order to study in depth the relationship between xanthophyll cycle and NPQ. These two processes were significantly related only during the gradually increasing light periods and not during stable light periods, where NPQ and zeaxanthin were decoupled. This result reveals that NPQ is a photoprotective process developed by algae only when cells are experiencing increasing PFD or in response to stressful light variations, for instance after a sudden light shift. Results showed that the photobiological properties of Picochlorum strain RCC 237 seem to be well related to the surface water characteristics, as it is able to maintain its photosynthetic characteristics under different PFDs and to quickly activate the xanthophyll cycle under high light.