Reduced Na+ and K+ permeability of K+ channel in plasma membrane isolated from roots of salt-tolerant mutant of wheat

The Na+ and K+ permeability of K+ channel in plasma membrane, isolated from roots of the salt-tolerant mutant of wheat, was lower than that of wild ty pe in 100 mmol/L KCl and NaCl solution. The opening frequency of K+ channel of the mutant reduced more significantly than that of wild type in two kin ds of solution mentioned above. It is assumed that the reduction of opening frequency mainly contributes to the Na+ and K+ permeability of K+ channel of the mutant. The electric conductance of single-channel of the mutant was similar to that of wild type and the main difference between them was exhi bited as the opening frequency. Their K+/Ka(+) selectivity of K+ channel ha d no significant difference. The K+/Na+ selectivity of the mutant and wild type was 3.35 and 3.18 respectively.