| Can the progressive increase of C₄ bundle sheath leakiness at low PFD be explained by incomplete suppression of photorespiration? | |
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MedLine Citation:
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PMID: 20561250 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The ability to concentrate CO₂ around Rubisco allows C₄ crops to suppress photorespiration. However, as phosphoenolpyruvate regeneration requires ATP, the energetic efficiency of the C₄ pathway at low photosynthetic flux densities (PFD) becomes a balancing act between primary fixation and concentration of CO₂ in mesophyll (M) cells, and CO₂ reduction in bundle sheath (BS) cells. At low PFD, retro-diffusion of CO₂ from BS cells, relative to the rate of bicarbonate fixation in M cells (termed leakiness φ), is known to increase. This paper investigates whether this increase in ϕ could be explained by incomplete inhibition of photorespiration. The PFD response of φ was measured at various O₂ partial pressures in young Zea mays plants grown at 250 (LL) and 750 µmol m⁻² s⁻¹ PFD (HL). φ increased at low PFD and was positively correlated with O₂ partial pressure. Low PFD during growth caused BS conductance and interveinal distance to be lower in the LL plants, compared to the HL plants, which correlated with lower φ. Model analysis showed that incomplete inhibition of photorespiration, especially in the HL plants, and an increase in the relative contribution of mitochondrial respiration at low PFD could explain the observed increases in φ. |
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Authors:
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Johannes Kromdijk; Howard Griffiths; Hans E Schepers |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Plant, cell & environment Volume: 33 ISSN: 1365-3040 ISO Abbreviation: Plant Cell Environ. Publication Date: 2010 Nov |
Date Detail:
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Created Date: 2010-10-22 Completed Date: 2011-01-24 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9309004 Medline TA: Plant Cell Environ Country: United States |
Other Details:
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Languages: eng Pagination: 1935-48 Citation Subset: IM |
Copyright Information:
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© 2010 Blackwell Publishing Ltd. |
Affiliation:
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Physiological Ecology, Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB23EA, UK. wannekromdijk@gmail.com |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Carbon Dioxide
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metabolism* Carbon Isotopes / analysis Cell Respiration Chlorophyll / analysis Models, Biological Oxygen / analysis* Photosynthesis* Photosystem II Protein Complex / physiology Ribulose-Bisphosphate Carboxylase / metabolism Zea mays / physiology* |
| Chemical | |
Reg. No./Substance:
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0/Carbon Isotopes; 0/Photosystem II Protein Complex; 124-38-9/Carbon Dioxide; 1406-65-1/Chlorophyll; 7782-44-7/Oxygen; EC 4.1.1.39/Ribulose-Bisphosphate Carboxylase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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