Fig. 6.

Effect of low pH and combined low pH plus 50 μM Al³⁺ on K⁺ fluxes measured at the distal elongation zone of 4- to 5-day-old Arabidopsis thaliana roots. The low-pH and combined low-pH/Al³⁺ treatments were imposed at time=0; the data recorded in the first 5 min before time=0 represent K⁺ fluxes at pH 5.5. Negative K⁺ flux values indicate efflux, and positive values indicate influx. Error bars are ±SE (n=10–12 seedlings). Arabidopsis seedlings were conditioned in basal salt medium (BSM; 0.1 mM CaCl₂+1 mM KCl+0.2 mM MgCl₂, pH 5.5) for 20 min before treatments were imposed in unbuffered BSM.