Flow–Force theory and modelling nitrogen uptake (Viewpoint)

Recent molecular and histochemical analyses of nitrate transporters have cast doubt on the ability of the Enzyme–Substrate interpretation of analysis of nitrate influx isotherms to improve modelling of N uptake in agronomic models. Le Deunff and Malagoli advocate the use an alternative formalism, the Flow–Force theory, to describe ion isotherms based upon biophysical ‘flows and forces’ relationships of non-equilibrium thermodynamics. This formalism can be combined easily with changes in the nitrate influx rate induced by climatic and in planta factors formalized by polynomial curves. They argue that application of the Flow–Force formalism allows nitrate uptake to be modelled in a more realistic manner, and allows scaling-up in time and space of the regulation of nitrate uptake across the plant growth cycle.