Figure 9.

nhx1 nhx2 Mutants Are Sensitive to Osmotic Stress.

Wild-type (Col-0) and nhx1 nhx2 mutant lines L2 and L14 were grown individually in capped test tubes adapted to hydroponic culture in LAK medium with 1 mM KCl for 3 weeks and then transferred to LAK medium with 20% PEG6000. The fresh weight of plants (n = 4 per line) was determined at the indicated times. Single mutants with alleles nhx1-2, nhx1-1, and nhx2-1, carried in parallel, produced intermediate results that have been removed for simplicity.

(A) Visual appearance of dehydration symptoms during the assay.

(B) Fresh weight of plants from the onset of stress to completion of the hyperosmotic treatment. Data are presented as water content relative to initial values before treatment.

(C) Wild-type and mutant plants recovering from hyperosmotic stress. Arrows indicate wilted flower buds in the mutants. Note small siliques in the mutants.