Carbon dioxide exchange rates of whole plants were measured as follows:( 1) in assimilation chambers (semi-open system), for plants from all groups (Cl-C6).
The Pn data measured on plants of the C4 and C5 cultivations (cv. “Line”) were separated in two data sets; one set was used for identification of the model parameters and the second set for their validation. The data obtained on plants of Cl, C2 and C3 groups (cv. “Heidi”), and C6 group (Rosalie) were used to test the extrapolative capacity of the model (different cultivars and greater leaf areas).