Interactions between carbon dioxide and oxygen in the photosynthesis of three species of marine red macroalgae |
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Authors: | David J. Sherlock John A. Raven |
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Affiliation: | 1. Division of Environmental and Applied Biology, School of Life Sciences , University of Dundee , Dundee , DD1 4HN;2. Department of Biology , University of York , York , YO11 5YW;3. Division of Environmental and Applied Biology, School of Life Sciences , University of Dundee , Dundee , DD1 4HN |
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Abstract: | Summary Red algae have the highest known selectivity factor (Srel) for CO2 over O2 of ribulose bisphosphate carboxylase-oxygenase (RUBISCO). This allows the prediction that a red alga relying on diffusive supply of CO2 to RUBISCO from air-equilibrated solution should have less O2 inhibition of photosynthesis than would an otherwise similar non-red alga with a lower Srel of RUBISCO. Furthermore, RUBISCO shows an increased Srel values at low temperatures. The prediction that O 2inhibition of photosynthesis should be small for marine red algae relying on diffusive CO2 entry growing in the North Sea with an annual temperature range of 4–16°C was tested in O2 electrode experiments at 12°C. Phycodrys rubens and Plocamium cartilagineum, which rely on diffusive CO2 entry showed, as predicted, only a small inhibition at lower inorganic C concentrations. Palmaria palmata, which has a CO2 concentrating mechanism, had the expected negligible O 2 inhibition of photosynthesis at any inorganic C concentration except (non-significantly) for saturating inorganic C. |
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Keywords: | CO2 O2 Photosynthesis Red algae |
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