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.