Carbon dioxide exchange of Alnus rubra : A mathematical model.

The CO2 exchange response of plants to multiple environmental variables is often difficult to frame for purposes of comparison. In this paper, a nonlinear model relating CO2 exchange to light and temperature is derived from experimental curves determined in other investigations. Parameter values, determined from a least-squares fit of the model to CO2 exchange data, are useful for comparing responses to light and temperature in terms of seasonal phenology, population heterogeneity, or species variation.The model was fitted to CO2 exchange data of a group of 40 Alnus rubra Bong. (red alder) seedlings for steady-state combinations of light and temperature. The average deviation of the data from the model was ±6.7%. This steady-state expression satisfactorily predicted CO2 exchange for dynamic conditions of light and temperature occurring in a diurnal cycle.