Respiratory metabolism of illuminated leaves depends on CO₂ and O₂ conditions

Day respiration is the process by which nonphotorespiratory CO₂ is produced by illuminated leaves. The biological function of day respiratory metabolism is a major conundrum of plant photosynthesis research: because the rate of CO₂ evolution is partly inhibited in the light, it is viewed as either d...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2008-01, Vol.105 (2), p.797-802
Main Authors: Tcherkez, Guillaume, Bligny, Richard, Gout, Elizabeth, Mahé, Aline, Hodges, Michael, Cornic, Gabriel
Format: Article
Language:English
Subjects:
Adenosine Diphosphate - chemistry
Adenosine Triphosphate - chemistry
Atoms
Biochemistry, Molecular Biology
Biological Sciences
Carbon dioxide
Carbon Dioxide - metabolism
Carbon isotopes
Carbon Isotopes - chemistry
cell respiration
Cluster Analysis
Decarboxylation
gas exchange
gas production (biological)
Gene Expression Regulation, Plant
Glycolysis
Leaves
Life Sciences
Light
Magnetic Resonance Spectroscopy
Molecules
oxygen
Oxygen - metabolism
Oxygen Consumption
Phosphorylation
Photorespiration
Photosynthesis
Plant Leaves - metabolism
Plant Physiological Phenomena
Plants
Respiration
tricarboxylic acid cycle
Xanthium strumarium
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Summary:Day respiration is the process by which nonphotorespiratory CO₂ is produced by illuminated leaves. The biological function of day respiratory metabolism is a major conundrum of plant photosynthesis research: because the rate of CO₂ evolution is partly inhibited in the light, it is viewed as either detrimental to plant carbon balance or necessary for photosynthesis operation (e.g., in providing cytoplasmic ATP for sucrose synthesis). Systematic variations in the rate of day respiration under contrasting environmental conditions have been used to elucidate the metabolic rationale of respiration in the light. Using isotopic techniques, we show that both glycolysis and the tricarboxylic acid cycle activities are inversely related to the ambient CO₂/O₂ ratio: day respiratory metabolism is enhanced under high photorespiratory (low CO₂) conditions. Such a relationship also correlates with the dihydroxyacetone phosphate/Glc-6-P ratio, suggesting that photosynthetic products exert a control on day respiration. Thus, day respiration is normally inhibited by phosphoryl (ATP/ADP) and reductive (NADH/NAD) poise but is up-regulated by photorespiration. Such an effect may be related to the need for NH₂ transfers during the recovery of photorespiratory cycle intermediates.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.0708947105