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Authors Winter, K; Garcia, M; Virgo, A; Holtum, JAM
Author Full Name Winter, Klaus; Garcia, Milton; Virgo, Aurelio; Holtum, Joseph A. M.
Title Operating at the very low end of the crassulacean acid metabolism spectrum: Sesuvium portulacastrum (Aizoaceae)
Source JOURNAL OF EXPERIMENTAL BOTANY
Language English
Document Type Article
Author Keywords Crassulacean acid metabolism; CO2 assimilation; C-4 photosynthesis; facultative CAM; salt tolerance; Sesuvium portulacastrum; succulence
Keywords Plus C-4 PHOTOSYNTHESIS; C-3-C-4 INTERMEDIATE; CAM PHOTOSYNTHESIS; LEAF ANATOMY; EVOLUTION; EUPHORBIA; CO2; PHYLOGENETICS; DIVERSITY; PLANTS
Abstract Demonstration of crassulacean acid metabolism (CAM) in species with low usage of this system relative to C-3-photosynthetic CO2 assimilation can be challenging experimentally but provides crucial information on the early steps of CAM evolution. Here, weakly expressed CAM was detected in the well-known pantropical coastal, leaf-succulent herb Sesuvium portulacastrum, demonstrating that CAM is present in the Sesuvioideae, the only sub-family of the Aizoaceae in which it had not yet been shown conclusively. In outdoor plots in Panama, leaves and stems of S. portulacastrum consistently exhibited a small degree of nocturnal acidification which, in leaves, increased during the dry season. In potted plants, nocturnal acidification was mainly facultative, as levels of acidification increased in a reversible manner following the imposition of short-term water-stress. In drought-stressed plants, nocturnal net CO2 exchange approached the CO2-compensation point, consistent with low rates of CO2 dark fixation sufficient to eliminate respiratory carbon loss. Detection of low-level CAM in S. portulacastrum adds to the growing number of species that cannot be considered C-3 plants sensu stricto, although they obtain CO2 principally via the C-3 pathway. Knowledge about the presence/absence of low-level CAM is critical when assessing trajectories of CAM evolution in lineages. The genus Sesuvium is of particular interest because it also contains C-4 species.
Author Address [Winter, Klaus; Garcia, Milton; Virgo, Aurelio; Holtum, Joseph A. M.] Smithsonian Trop Res Inst, POB 0843-03092, Balboa, Ancon, Panama; [Holtum, Joseph A. M.] James Cook Univ, Coll Sci & Engn, Ctr Trop Biodivers & Climate Change, Townsville, Qld 4811, Australia
Reprint Address Winter, K (corresponding author), Smithsonian Trop Res Inst, POB 0843-03092, Balboa, Ancon, Panama.
E-mail Address winterk@si.edu
Funding Agency and Grant Number Smithsonian Tropical Research Institute (STRI)Smithsonian InstitutionSmithsonian Tropical Research Institute; Australian Research Council Discovery ProjectAustralian Research Council [DP160100098]
Funding Text This research was supported by the Smithsonian Tropical Research Institute (STRI) and the Australian Research Council Discovery Project (DP160100098). We acknowledge the assistance of Jorge Aranda who maintained the experimental plots at Gamboa.
Times Cited 6
Total Times Cited Count (WoS, BCI, and CSCD) 6
Publisher OXFORD UNIV PRESS
Publisher City OXFORD
Publisher Address GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND
ISSN 0022-0957
29-Character Source Abbreviation J EXP BOT
ISO Source Abbreviation J. Exp. Bot.
Publication Date NOV 15
Year Published 2019
Volume 70
Issue 22
Special Issue SI
Beginning Page 6561
Ending Page 6570
Digital Object Identifier (DOI) 10.1093/jxb/ery431
Page Count 10
Web of Science Category Plant Sciences
Subject Category Plant Sciences
Document Delivery Number KB9LP
Unique Article Identifier WOS:000506809000007
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