Photosynthetic Response of Nereocystis Luetkeana (Phaeophyta) to High Light
Department or Administrative Unit
Biological Sciences
Document Type
Article
Author Copyright
© 2011 Japanese Society of Phycology
Publication Date
5-12-2011
Journal
Phycological Research
Abstract
Photosynthetic response to high light was determined for Bull kelp, Nereocystis luetkeana (K. Mertens) Postels and Ruprecht in order to understand how this species is affected by short-term fluctuations in irradiance. Exposure of N. luetkeana blades to high intensity photosynthetically active radiation (1000 µmol photons m−2 s–1) caused increased non-photochemical quenching of fluorescence and higher de-epoxidation ratios for xanthophyll pigments indicating that energy-quenching xanthophylls were used to protect blades against photoinhibition. Despite initiation of these photoprotective mechanisms, maximum photochemical efficiency of photosystem II (Fv/Fm) decreased 40% in response to a 60 min exposure to 1000 µmol photons m−2 s–1 photosynthetically active radiation indicating that photoinhibition had occurred. Light-saturated rates of oxygen evolution were not changed significantly by the high light treatment. Recovery of maximum photochemical efficiency of photosystem II to within 8% of initial values occurred after a 300-min dim light period. Younger sections of the blades were slightly more susceptible to high light damage than older sections. Middle sections of the blades were more prone to light-induced damage at water temperatures of 7°C or 18°C, as compared to 13°C. Exposure to biologically effective ultraviolet-B radiation (UV-Bbe) (up to 4.5 kJ m–2 day–1) in photoinhibitory light conditions did not significantly affect light-induced damage to photosystem II.
Recommended Citation
Poulson, M.E., McNeil, A.J. & Donahue, R.A. (2011). Photosynthetic response of Nereocystis luetkeana (Phaeophyta) to high light. Phycological Research 59(3), 156-165. DOI: 10.1111/j.1440-1835.2011.00614.x
Comments
This article was originally published in Phycological Research. The full-text article from the publisher can be found here.
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