Bryophyte gas-exchange dynamics along varying hydration status reveal a significant carbonyl sulphide (COS) sink in the dark and COS source in the light
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Gimeno, T., Ogée, J., Evans, J., Gibon, Y., West, J., Burlett, R., Jones, S., et al. (2017). Bryophyte gas-exchange dynamics along varying hydration status reveal a significant carbonyl sulphide (COS) sink in the dark and COS source in the light. New Phytologist https://doi.org/10.1111/nph.14584
Carbonyl sulphide (COS) is a potential tracer of gross primary productivity (GPP), assuming a unidirectional COS flux into the vegetation that scales with GPP. However, carbonic anhydrase (CA), the enzyme that hydrolyses COS, is expected to be light independent, and thus plants without stomata should continue to take up COS in the dark. We measured net CO2 (A(C) ) and COS (A(S) ) uptake rates from two astomatous bryophytes at different relative water contents (RWCs), COS concentrations, temperatures and light intensities. We found large A(S) in the dark, indicating that CA activity continues without photosynthesis. More surprisingly, we found a nonzero COS compensation point in light and dark conditions, indicating a temperature-driven COS source with a Q10 (fractional change for a 10°C temperature increase) of 3.7. This resulted in greater A(S) in the dark than in the light at similar RWC. The processes underlying such COS emissions remain unknown. Our results suggest that ecosystems dominated by bryophytes might be strong atmospheric sinks of COS at night and weaker sinks or even sources of COS during daytime. Biotic COS production in bryophytes could result from symbiotic fungal and bacterial partners that could also be found on vascular plants.
Marchantia polymorpha, Scleropodium purum, carbohydrates, desiccation, liverwort, moss, protein, respiration
Funding was provided by the European Research Council (ERC) early career starting grant SOLCA (grant no. 338264) and the French Agence National de la Recherche (ANR) project ORCA. T.E.G. was funded by the IdEx post-doctoral programme of the Université de Bordeaux and by a Marie Skłodowska-Curie Intra-European fellowship (grant no. 653223). J.R. was funded by NERC grant NE/M00113X/1.
External DOI: https://doi.org/10.1111/nph.14584
This record's URL: https://www.repository.cam.ac.uk/handle/1810/264426