Sensitivity of nhx1 nhx2 Mutant Plants to External K+.
(A) One-week-old seedlings of Col-0 and of mutant line L2 grown in LAK medium with 1 mM KCl were transferred to fresh hydroponic LAK medium supplemented with the indicated concentrations of KCl. After 2 weeks, plants were collected and their shoot and root fresh weight were determined.
(B) Average fresh weight and sd values (n = 8 per line) of plants shown in (A). Differences between the mutant line and Col-0 were statistically significant at P < 0.01 (a) or P < 0.05 (b) by the Fisher’s LSD method. Mutant line 14 produced identical results to L2.
(C) Average K+ and water content in shoots of Col-0 and nhx1 nhx2 mutant plants of line L2 (n = 6 per line) grown as in (A) in hydroponic LAK medium with the indicated K+ concentrations. K+ content is given as a percent of dry weight (DW; top panel) and millimolar concentration (bottom panel). Water content is given in the middle panel. Statistical differences by the LSD method of mutant relative to the wild type are indicated by letters; a, P < 0.01; b, P < 0.05; c, P < 0.1. Line 14 produced identical results to L2.