Quantitative analysis of photosynthetic carbon metabolism in protoplasts and intact leaves of barley. Determination of carbon fluxes and pool sizes of metabolites in different cellular compartments.

Rates of carbon fluxes and pool sizes of photosynthetic metabolites in different cellular compartments of barley protoplasts were calculated from the time curves of their labeling in the medium of ¹⁴CO₂. Using membrane filtration procedure, kinetics of ¹⁴C incorporation into the products of steady-state photosynthesis was determined separately in chloroplasts, mitochondria and cytosol of barley protoplasts illuminated for different periods in the air containing ¹⁴CO₂. To extract the quantitative information, analytical labeling functions P(t) describing the dependence of ¹⁴C content in the primary, intermediate and end products of a linear reaction chain upon the duration of tracer feeding have been derived.