Table I. Steady-state K⁺ fluxes, compartmentation, and electrophysiology of intact barley seedling roots.

One-week-old barley seedlings were grown on full nutrient medium supplemented with 10 mm NH₄⁺ and either 0.0225 or 0.1125 mm K⁺. ΔΨ_m measurements were taken from root epidermal and cortical cells 2 to 3 cm from the root tip. E_K⁺ and predicted [K⁺]_cyt were determined with the Nernst equation. Error values indicate se of six to eight replicates.

[K+]ext	Influx	Efflux	Net Flux	Efflux-Influx Ratio	Half-Time	ΔΨm	EK+	[K+]cyt
								Predicted	Measured
mm	µmol g−1 h−1				min	mV		mm
0.0225	0.52 ± 0.03	0.27 ± 0.02	0.25 ± 0.02	0.52 ± 0.03	32.90 ± 2.92	−143.6 ± 2.7	−153.8	5.57	8.24 ± 0.69
0.1125	1.89 ± 0.13	0.57 ± 0.05	1.32 ± 0.10	0.30 ± 0.01	32.50 ± 4.69	−136.2 ± 3.0	−144.1	20.95	28.39 ± 3.40