Four Arabidopsis accessions carrying CLSY1 allele-D (Col-0, Mnz-0, Pog-0, Ove-0, Rak2; black) and two accessions carrying allele-E (Chat-1 and Fei-0; red) were crossed with Col-0 wild type (Col-0; blue) or Col-0 clsy1-7 mutant (clsy1-7; green). a Phenotype of F1 plants grown on low K. b Means ± S.E of lateral root number in heterozygous F1 plants and parental genotypes from three independent experiments. Number of individual roots analysed in control/low K: n = 30/30 (Col-0 x Col-0), 32/32 (Col-0 × clsy1-7), 49/48 (Mnz-0 x Col-0), 37/45 (Mnz-0 × clsy1-7), 25/43 (Pog-0 x Col-0), 32/49 (Pog-0 × clsy1-7), 36/44 (Ove-0 x Col-0), 38/38 (Ove-0 × clsy1-7), 28/29 (Rak-2 x Col-0), 28/28 (Rak-2 × clsy1-7), 39/50 (Fei-0 x Col-0), 33/51 (Fei-0 × clsy1-7), 40/38 (Chat-1 x Col-0), 28/50 (Chat-1 × clsy1-7), 14/19 (Col-0 wild type), 18/22 (clsy1-7), 13/17 (Mnz-0), 17/9 (Pog-0), 11/17 (Ove-0), 16/16 (Rak-2), 21/23 (Fei-0), and 14/23 (Chat-1). The allele x background interaction tests were performed using two-way ANOVA, and significant differences are indicated by asterisks (*P < 0.05 and **P < 0.001). c Relative (low K/control) shoot dry weights (DWs) of parental and F1 plants from three independent experiments. Centre lines and crosses within the box plots represent sample medians and means. Number of roots analysed (n) for each genotype and condition is given above the graph. Box boundaries indicate the 25th and 75th percentiles; whiskers extend to 1.5 times the interquartile range. Statistical analysis was carried out as in (b). The source data of b, c are provided in a Source Data file.