Oscillatory model of crassulacean acid metabolism:: structural analysis and stability boundaries with a discrete hysteresis switch

We propose a simple oscillatory model of crassulacean acid metabolism (CAM) describing the CO2 uptake and nocturnal acidification of CAM plants by a system of coupled non-linear differential equations. Large differences in the content of metabolite pools are treated using a pseudo-steady-state approach. For the first time, simulations of the CAM cycle investigate its dependence on all three major control parameters simultaneously: temperature, photon flux density and external CO2 concentration. Under stationary conditions in time the model shows either endogenous rhythmicity or two distinct steady states. Stability boundaries are calculated in parameter space.