Nitrogen uptake/transport capacity

Uptake capacity is dependent on the number and eiEciency of membrane transport proteins. It is not really known how the numbers of transporters (e.g. ammonium or nitrate) per cell varies as a function of physiological state, or how the kinetics of transport may be a function of the protein structure of the transporters themselves. Some studies indicate that the number of transporters per cell increase with nitrogen limitation, but kinetic data suggests otherwise and that transporter numbers are more or less constant as a function of growth rate under N limitation... 

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