Inorganic carbon uptake during photosynthesis. I. A theoretical analysis using the isotopic disequilibrium technique

Journal Article · Tue Apr 01 04:00:00 EST 1986 · Plant Physiol.; (United States)

DOI:https://doi.org/10.1104/pp.80.4.863· OSTI ID:6991200

Espie, G S; Colman, B

Equations have been developed which quantitatively predict the theoretical time-course of photosynthetic /sup 14/C incorporation when CO/sub 2/ or HCO/sub 3//sup -/ serves as the sole source of exogenous inorganic carbon taken up for fixation by cells during steady state photosynthesis. Comparison between the shape of theoretical CO/sub 2/ or HCO/sub 3//sup -/) and experimentally derived time-courses of /sup 14/C incorporation permits the identification of the major species of inorganic carbon which crosses the plasmalemma of photosynthetic cells and facilitates the detection of any combined contribution of CO/sub 2/ and HCO/sub 3//sup -/ transport to the supply of intracellular inorganic carbon. The ability to discriminate between CO/sub 2/ or HCO/sub 3//sup -/ uptake relies upon monitoring changes in the intracellular specific activity (by /sup 14/C fixation) which occur when the inorganic carbon, present in the suspending medium, is in a state of isotopic disequilibrium. The presence of intracellular carbonic anhydrases or some other catalyst of the CO/sub 2/-HCO/sub 3//sup -/ interconversion reaction is required for quantitatively accurate predictions. Analysis of equations describing the rate of /sup 14/C incorporation provides two methods by which any contribution of HCO/sub 3//sup -/ ions to net photosynthetic carbon uptake can be estimated.

• Research Organization: York Univ., Downsview, Ontario
• OSTI ID: 6991200
• Journal Information: Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 80:4; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
CARBON
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON DIOXIDE FIXATION
CARBON OXIDES
CARBONIC ACID
CHALCOGENIDES
CHEMICAL REACTIONS
ELEMENTS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MEASURING METHODS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PLANT CELLS
SOLUTES
SYNTHESIS
TRACER TECHNIQUES
UPTAKE