Low internal air space in plants with crassulacean acid metabolism may be an anatomical spandrel.

Autor: Leverett A; School of Life Sciences, University of Essex, Wivenhoe Campus, Essex, CO4 3SQ, UK.; Department of Plant Sciences, University of Cambridge, Downing St., Cambridge, CB2 3EA, UK., Borland AM; School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK., Inge EJ; School of Life Sciences, University of Essex, Wivenhoe Campus, Essex, CO4 3SQ, UK., Hartzell S; Department of Civil and Environmental Engineering, Portland State University, 1930 SW 124th Ave., Portland, OR, USA.
Jazyk: angličtina
Zdroj: Annals of botany [Ann Bot] 2023 Nov 25; Vol. 132 (4), pp. 811-817.
DOI: 10.1093/aob/mcad109
Abstrakt: Crassulacean acid metabolism (CAM) is a photosynthetic adaptation found in at least 38 plant families. Typically, the anatomy of CAM plants is characterized by large photosynthetic cells and a low percentage of leaf volume consisting of internal air space (% IAS). It has been suggested that reduced mesophyll conductance (gm) arising from low % IAS benefits CAM plants by preventing the movement of CO2 out of cells and ultimately minimizing leakage of CO2 from leaves into the atmosphere during day-time decarboxylation. Here, we propose that low % IAS does not provide any adaptive benefit to CAM plants, because stomatal closure during phase III of CAM will result in internal concentrations of CO2 becoming saturated, meaning low gm will not have any meaningful impact on the flux of gases within leaves. We suggest that low % IAS is more likely an indirect consequence of maximizing the cellular volume within a leaf, to provide space for the overnight storage of malic acid during the CAM cycle.
(© The Author(s) 2023. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
Databáze: MEDLINE
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