The case for cytosolic NO3- heterostasis: A critique of a recently proposed model

Abstract

A model recently proposed by Siddiqi & Glass (Plant, Cell, and Environment 25, 1211-1217, 2002) attempts to reconcile discrepancies in the measurement of cytosolic nitrate concentrations ([NO3-]cyt) in plant root cells, specifically between low (∼4 mM) homeostatic values reported in studies using ion-specific microelectrodes on the one hand, and wide fluctuations in [NO3-]cyt reported in other studies, especially those using compartmental analysis by tracer efflux (CATE). Although Siddiqi & Glass concede that cytosolic NO3- homeostasis, as determined by microelectrodes, is at odds with certain experimental observations, they nevertheless promote a model that takes microelectrode readings at ..