Photosynthesis and Metabolism of Seagrasses

Anthony W.D. Larkum; Mathieu Pernice; Martin Schliep; Peter Davey; Milan Szabo; John A Raven; Mads Lichtenberg; Kasper Elgetti Brodersen; Peter J Ralph

doi:10.1007/978-3-319-71354-0_11

Photosynthesis and Metabolism of Seagrasses

Anthony W.D. Larkum, Mathieu Pernice, Martin Schliep, Peter Davey, Milan Szabo, John A Raven, Mads Lichtenberg, Kasper Elgetti Brodersen, Peter J Ralph

Marine Biology

7 Citations (Scopus)

Abstract

Seagrasses have a unique leaf morphology where the major site for chloroplasts is in the epidermal cells, stomata are absent and aerenchyma is present inside the epidermis. This means that the major site for photosynthesis is in the epidermis. Furthermore the lack of stomata means that the route for carbon uptake is via inorganic carbon (C _i ) uptake across the vestigial cuticle and through the outer plasma membranes. Since the leaf may at times be in an unstirred situation diffusion through an unstirred layer outside the leaf may be a large obstacle to carbon uptake. The existence of a carbon concentrating mechanism is discussed, but its existence to date is not proven. Active bicarbonate uptake across the plasmalemma does not seem to operate; an external carbonic anhydrase and an extrusion of protons seem to play a role in enhancing CO ₂ uptake. There is some evidence that a C4 mechanism plays a role in carbon fixation but more evidence from "omics" is required. Photorespiration certainly occurs in seagrasses and an active xanthophyll cycle is present to cope with damaging high light, but both these biochemical mechanisms need further work. Finally, epiphytes pose a problem which impedes the uptake of C _i and modifies the light environment inside the leaves.

Original language	English
Title of host publication	Seagrasses of Australia : Structure, Ecology and Conservation
Editors	Anthony W. D. Larkum, Gary A. Kendrick, Peter J. Ralph
Publisher	Springer
Publication date	27 Jul 2018
Pages	315-342
Chapter	11
ISBN (Print)	978-3-319-71352-6
ISBN (Electronic)	978-3-319-71354-0
DOIs	https://doi.org/10.1007/978-3-319-71354-0_11
Publication status	Published - 27 Jul 2018

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Larkum, A. W. D., Pernice, M., Schliep, M., Davey, P., Szabo, M., Raven, J. A., Lichtenberg, M., Brodersen, K. E., & Ralph, P. J. (2018). Photosynthesis and Metabolism of Seagrasses. In A. W. D. Larkum, G. A. Kendrick, & P. J. Ralph (Eds.), Seagrasses of Australia: Structure, Ecology and Conservation (pp. 315-342). Springer. https://doi.org/10.1007/978-3-319-71354-0_11

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Photosynthesis and Metabolism of Seagrasses

Abstract

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