Xanthophyll cycle
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The xanthophyll cycle involves conversions of pigments from a non-energy-quenching form to energy-quenching forms. This is a way to reduce the absorption cross-section of the light harvesting antenna, and thus to reduce the amount of energy that reaches the photosynthetic reaction centers. Reducing the light harvesting antenna is one of the main ways of protecting against photoinhibition and changes in the xanthophyll cycling takes place on a time scale of minutes to hours (Falkowski & Raven 1997).
In higher plants there are three carotenoid pigments that are active in the xanthophyll cycle: violoxanthin, antheraxanthin and zeaxanthin. During light stress violoxanthin is converted to antheraxanthin and zeaxanthin, which functions as photoprotective pigments.
In diatoms and dinoflagellates the xanthophyll cycle consists of the pigment diadinoxanthin, which is transformed into diatoxanthin (diatoms) or dinoxanthin (dinoflagellates), at high light (Jeffrey & Vesk 1997).
[edit] References
- Demmig-Adams, B & W. W. Adams, 2006. Photoprotection in an ecological context: the remarkable complexity of thermal energy dissipation, New Phytologist, 172: 11–21.
- Falkowski, P. G. & J. A. Raven, 1997, Aquatic photosynthesis. Blackwell Science, 375 pp.
- Jeffrey, S. W. & M. Vesk, 1997. Introduction to marine phytoplankton and their pigment signatures. In Jeffrey, S. W., R. F. C. Mantoura & S. W. Wright (eds.), Phytoplankton pigments in oceanography, pp 37-84. – UNESCO Publishing, Paris.
