Phlorotannin Production and Lipid Oxidation as a Potential Protective Function Against High Photosynthetically Active and UV Radiation in Gametophytes of Alaria esculenta (Alariales, Phaeophyceae)

Authors

  • Franciska S. Steinhoff,

    Corresponding author
    1. Department of Marine Botany, University of Bremen, Bremen, Germany
    2. Section Functional Ecology, Department Seaweed Biology, Alfred-Wegener Institute for Polar and Marine Research, Bremerhaven, Germany
      Corresponding author email: Franciska.Steinhoff@ntnu.no (Franciska S. Steinhoff)
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  • Martin Graeve,

    1. Section Ecological Chemistry, Alfred-Wegener Institute for Polar and Marine Research, Bremerhaven, Germany
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  • Krzysztof Bartoszek,

    1. Mathematical Sciences, Chalmers University of Technology and the University of Gothenburg, Gothenburg, Sweden
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  • Kai Bischof,

    1. Department of Marine Botany, University of Bremen, Bremen, Germany
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  • Christian Wiencke

    1. Section Functional Ecology, Department Seaweed Biology, Alfred-Wegener Institute for Polar and Marine Research, Bremerhaven, Germany
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Corresponding author email: Franciska.Steinhoff@ntnu.no (Franciska S. Steinhoff)

Abstract

Radiation damage can inter alia result in lipid peroxidation of macroalgal cell membranes. To prevent photo-oxidation within the cells, photoprotective substances such as phlorotannins are synthesized. In the present study, changes in total fatty acids (FA), FA composition and intra/extracellular phlorotannin contents were determined by gas chromatography and the Folin-Ciocalteu method to investigate the photoprotective potential of phlorotannins to prevent lipid peroxidation. Alaria esculenta juveniles (Phaeophyceae) were exposed over 20 days to high/low photosynthetically active radiation (PAR) in combination with UV radiation (UVR) in the treatments: PAB (low/high PAR + UV-B + UV-A), PA (low/high PAR + UV-A) or low/high PAR only. While extracellular phlorotannins increased after 10 days, intracellular phlorotannins increased with exposure time and PA and decreased under PAB. Interactive effects of time:radiation wavebands, time:PAR dose as well as radiation wavebands:PAR dose were observed. Low FA contents were detected in the PA and PAB treatments; interactive effects were observed between time:high PAR and PAB:high PAR. Total FA contents were correlated to extra/intracellular phlorotannin contents. Our results suggest that phlorotannins might play a role in intra/extracellular protection by absorption and oxidation processes. Changes in FA content/composition upon UVR and high PAR might be considered as an adaptive mechanism of the A. esculenta juveniles subjected to variations in solar irradiance.

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