Regulation of photorespiration in leaves: evidence that the fraction of ribulose bisphosphate oxygenated is conserved and stoichiometry fluctuates

Journal Article · Tue Apr 01 04:00:00 EST 1986 · Arch. Biochem. Biophys.; (United States)

DOI:https://doi.org/10.1016/0003-9861(86)90478-9· OSTI ID:5743156

Hanson, K R; Peterson, R B

Under steady-state conditions the combined system of the reductive photosynthetic cycle and the oxidative photorespiratory loop may be defined by two partitioning terms: the fraction of ribulose bisphosphate oxygenated and the fraction of glycolate carbon photorespired (the stoichiometry of photorespiration). A combination of physical and stereochemical methods has been used to estimate these partitionings for tobacco leaf discs. Inverted discs, as compared to normally oriented discs, were found to have greater net photosynthesis; their ratio of photorespiration to net photosynthesis was less, and less of their glycolate carbon was photorespired. An eightfold reduction of irradiance below that of full sunlight for inverted discs in normal air at 32 degrees C reduced both photosynthesis and photorespiration about threefold but had little effect on the partitioning of ribulose bisphosphate and glycolate. Increasing the temperature from 22 to 40 degrees C for inverted discs in normal air and 1000 microE m-2 s-1 irradiance had little effect on net photosynthesis but increased the ratio of photorespiration to net photosynthesis almost threefold; ribulose bisphosphate partitioning was little changed but the fraction of glycolate carbon photorespired more than doubled. If field-grown plants respond to temperature in a similar fashion, genetic intervention to reduce the increase in photorespiration stoichiometry with temperature could increase total daily carbon assimilation and hence improve crop yields.

• Research Organization: Connecticut Agricultural Experiment Station, New Haven
• OSTI ID: 5743156
• Journal Information: Arch. Biochem. Biophys.; (United States), Journal Name: Arch. Biochem. Biophys.; (United States) Vol. 1; ISSN ABBIA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
ENZYMES
LEAVES
OXIDES
OXIDOREDUCTASES
OXYGEN COMPOUNDS
OXYGENASES
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PLANTS
RESPIRATION
STEADY-STATE CONDITIONS
STOICHIOMETRY
SYNTHESIS
TEMPERATURE EFFECTS
TOBACCO