Abstract
The electrochemical potential differences \(\left( {\Delta \overline \mu _{{\rm K}^ + } } \right)\) for potassium, between excised barley (Hordeum vulgare L.) roots and external media containing 0.05 mM KCl+0.5 mM CaSO4, were determined over a 4-h period during which initially low-K+ roots accumulated K+ by pretreatment in 50 mM KCl plus 0.5 mM CaCl2. This pretreatment resulted in increased internal [K+], decreased K+ influx (as measured from 0.05 mM KCl+0.5 mM CaSO4) and decreased values of \(\Delta \overline \mu _{{\rm K}^ + }\). These observations indicate that the decline of K+ influx associated with increased internal K+ concentration cannot be accounted for by passive adjustment to the electrochemical gradient for this ion.
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Glass, A.D.M., Dunlop, J. The regulation of K+ influx in excised barley roots. Planta 145, 395–397 (1979). https://doi.org/10.1007/BF00388368
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DOI: https://doi.org/10.1007/BF00388368