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Carbon isotope discrimination as a diagnostic tool for C(4) photosynthesis in C(3)-C(4) intermediate species
The presence and activity of the C(4) cycle in C(3)-C(4) intermediate species have proven difficult to analyze, especially when such activity is low. This study proposes a strategy to detect C(4) activity and estimate its contribution to overall photosynthesis in intermediate plants, by using tunabl...
Autores principales: | , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Oxford University Press
2016
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4867892/ https://www.ncbi.nlm.nih.gov/pubmed/26862154 http://dx.doi.org/10.1093/jxb/erv555 |
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author | Alonso-Cantabrana, Hugo von Caemmerer, Susanne |
author_facet | Alonso-Cantabrana, Hugo von Caemmerer, Susanne |
author_sort | Alonso-Cantabrana, Hugo |
collection | PubMed |
description | The presence and activity of the C(4) cycle in C(3)-C(4) intermediate species have proven difficult to analyze, especially when such activity is low. This study proposes a strategy to detect C(4) activity and estimate its contribution to overall photosynthesis in intermediate plants, by using tunable diode laser absorption spectroscopy (TDLAS) coupled to gas exchange systems to simultaneously measure the CO(2) responses of CO(2) assimilation (A) and carbon isotope discrimination (Δ) under low O(2) partial pressure. Mathematical models of C(3)-C(4) photosynthesis and Δ are then fitted concurrently to both responses using the same set of constants. This strategy was applied to the intermediate species Flaveria floridana and F. brownii, and to F. pringlei and F. bidentis as C(3) and C(4) controls, respectively. Our results support the presence of a functional C(4) cycle in F. floridana, that can fix 12–21% of carbon. In F. brownii, 75–100% of carbon is fixed via the C(4) cycle, and the contribution of mesophyll Rubisco to overall carbon assimilation increases with CO(2) partial pressure in both intermediate plants. Combined gas exchange and Δ measurement and modeling is a powerful diagnostic tool for C(4) photosynthesis. |
format | Online Article Text |
id | pubmed-4867892 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | Oxford University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-48678922016-05-17 Carbon isotope discrimination as a diagnostic tool for C(4) photosynthesis in C(3)-C(4) intermediate species Alonso-Cantabrana, Hugo von Caemmerer, Susanne J Exp Bot Research Paper The presence and activity of the C(4) cycle in C(3)-C(4) intermediate species have proven difficult to analyze, especially when such activity is low. This study proposes a strategy to detect C(4) activity and estimate its contribution to overall photosynthesis in intermediate plants, by using tunable diode laser absorption spectroscopy (TDLAS) coupled to gas exchange systems to simultaneously measure the CO(2) responses of CO(2) assimilation (A) and carbon isotope discrimination (Δ) under low O(2) partial pressure. Mathematical models of C(3)-C(4) photosynthesis and Δ are then fitted concurrently to both responses using the same set of constants. This strategy was applied to the intermediate species Flaveria floridana and F. brownii, and to F. pringlei and F. bidentis as C(3) and C(4) controls, respectively. Our results support the presence of a functional C(4) cycle in F. floridana, that can fix 12–21% of carbon. In F. brownii, 75–100% of carbon is fixed via the C(4) cycle, and the contribution of mesophyll Rubisco to overall carbon assimilation increases with CO(2) partial pressure in both intermediate plants. Combined gas exchange and Δ measurement and modeling is a powerful diagnostic tool for C(4) photosynthesis. Oxford University Press 2016-05 2016-02-08 /pmc/articles/PMC4867892/ /pubmed/26862154 http://dx.doi.org/10.1093/jxb/erv555 Text en © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. http://creativecommons.org/licenses/by/3.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Research Paper Alonso-Cantabrana, Hugo von Caemmerer, Susanne Carbon isotope discrimination as a diagnostic tool for C(4) photosynthesis in C(3)-C(4) intermediate species |
title | Carbon isotope discrimination as a diagnostic tool for C(4) photosynthesis in C(3)-C(4) intermediate species |
title_full | Carbon isotope discrimination as a diagnostic tool for C(4) photosynthesis in C(3)-C(4) intermediate species |
title_fullStr | Carbon isotope discrimination as a diagnostic tool for C(4) photosynthesis in C(3)-C(4) intermediate species |
title_full_unstemmed | Carbon isotope discrimination as a diagnostic tool for C(4) photosynthesis in C(3)-C(4) intermediate species |
title_short | Carbon isotope discrimination as a diagnostic tool for C(4) photosynthesis in C(3)-C(4) intermediate species |
title_sort | carbon isotope discrimination as a diagnostic tool for c(4) photosynthesis in c(3)-c(4) intermediate species |
topic | Research Paper |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4867892/ https://www.ncbi.nlm.nih.gov/pubmed/26862154 http://dx.doi.org/10.1093/jxb/erv555 |
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