Table I.

Selectivity ratios for nonselective cation channels measured by patch clamping protoplasts from root cortex of Arabidopsis

Cation Tested	Permeability Relative to Na+
K+	1.49 ± 0.15
NH	1.24 ± 0.11
Rb+	1.15 ± 0.10
Cs+	1.1 ± 0.08
Li+	0.73 ± 0.07
TEA+	0.47 ± 0.04

Data were obtained on the basis of conductances over the 30 mV immediately negative of the reversal potential (Piñeros and Tester, 1995). Solutions contained 25 mm NaCl ⁺ 25 mm Cl⁻ salt of the test cation, all on a background of 0.5 mm CaCl₂. Values of currents for conductance calculations were obtained by subtraction of background currents caused by 25 mm NaCl. Cells used were insensitive to verapamil. Values are the average of three to four measurements ± se.