A Numerical Approach to Measurement of CO(2) Exchange Transients by Infrared Gas Analysis

Open flow-through systems coupled to infrared gas analyzers have been frequently employed in the study of CO(2) exchange transients such as the postillumination burst observed in leaves of C(3) plants. A major limitation associated with use of such systems is their non-steady state response to rapid changes in leaf CO(2) exchange rate. A previous publication outlined a numerical approach to model the analyzer response as a function of CO(2) exchange rate and thus permit estimation of the postillumination burst (Peterson 1983 Plant Physiol 73: 978-982). The model is critically analyzed within the framework of the physics of solute dispersion as previously described for linear flow systems. Thus, the numerical simulation is validated on the basis of physical principle. Additional improvements to the previous model are described which enhance the accuracy and efficiency of use of this technique for estimation of photorespiration.