Ethyl methane-sulfonate (EMS)-mutagenized Arabidopsis M-2 populations were screened in low-K+ medium using the root-bending assay. Forty-two putative low-k(+)-tolerant (lkt) mutants were selected from 150 000 tested M-2 seedlings, and two of these mutants maintained their low-K+-tolerant phenotype in their M-3 generations, respectively. Genetic analysis showed that either one of these two mutants has a monogenic recessive mutation in a nuclear gene, and that the two mutations in two independent mutants are allelic to each other.
