title: Life at the boundary: photosynthesis at the soil-fluid interface. A synthesis focusing on mosses.
abstract: Mosses are among the earliest branching embryophytes and probably originated not later than the early Ordovician when atmospheric CO2 was higher and O2 was lower than today. The C3 biochemistry and physiology of their photosynthesis suggests, by analogy with tracheophytes, that growth of extant bryophytes in high CO2 approximating Ordovician values would increase the growth rate. This occurs for many mosses, including Physcomitrella patens in suspension culture, although recently published transcriptomic data on this species at high CO2 and present-day CO2 show down-regulation of the transcription of several genes related to photosynthesis. It would be useful if transcriptomic (and proteomic) data comparing growth conditions are linked to measurements of growth and physiology on the same, or parallel, cultures. Mosses (like later-originating embryophytes) have been subject to changes in bulk atmospheric CO2 and O2 throughout their existence, with evidence, albeit limited, for positive selection of moss Rubisco. Extant mosses are subject to a large range of CO2 and O2 concentrations in their immediate environments, especially aquatic mosses, and mosses are particularly influenced by CO2 generated by, and O2 consumed by, soil chemoorganotrophy from organic C produced by tracheophytes (if present) and bryophytes.
authors: Permanent address: Division of Plant Sciences, University of Dundee at the James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK School of Plant Biology, The University of Western Australia, M084, 35 Stirling Highway, Crawley, WA 6009, Australia j.a.raven@dundee.ac.uk.
authors: John A
authors: JA
authors: Raven
authors: School of Plant Biology, The University of Western Australia, M084, 35 Stirling Highway, Crawley, WA 6009, Australia.
authors: Timothy D
authors: TD
authors: Colmer
mesh_terms: D005075:Biological Evolution; D044002:Bryophyta / Q000502:physiology*; D002245:Carbon Dioxide / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D010788:Photosynthesis; D012987:Soil
chemical_list: D012987:Soil; D002245:Carbon Dioxide; D010100:Oxygen
keywords: ABA; C3 biochemistry and physiology; adaptation to global change; bryophytes; decreased oxygen; hornworts; increased carbon dioxide; liverworts; mosses; photorespiration; transcriptomics.