Figure 2.

Nuclear auxin signaling modulates inner polar nuclear positioning. A to H, Nuclear position in trichoblasts of aldehyde-fixed 5-d-old seedling roots. A, Wild-type Columbia-0 (Col-0). B, ctr1^btk. C, ctr1^btk;axr2-1. D, ctr1^btk;arf7-1;arf19-1. E, A 1 μm NaOH solvent control (in MS-agar). F, Treatment with 300 nm 1-NAA in Col-0. G, Treatment with 300 nm 1-NAA in axr2-1. H, Treatment with 300 nm 1-NAA in arf7-1;arf19-1. Nuclei, 4′,6-Diamidino-2-phenylindole (DAPI; cyan) overlaid with a bright-field image. Dotted lines show inner lateral cell walls of trichoblasts. Asterisks indicate mispositioned nuclei. Arrowheads show basal and apical ends of cells. Bars = 20 µm. I to N, Quantitative analysis of nuclear position. I, Col-0 versus ctr1^btk. J, ctr1^btk versus ctr1^btk;axr2-1. K, ctr1^btk versus ctr1^btk;arf7-1;arf19-1. L, A 1 μm NaOH solvent control in MS-agar versus 300 nm 1-NAA in Col-0. M, Treatment with 300 nm 1-NAA, Col-0 versus 300 nm 1-NAA, axr2-1. N, Treatment with 300 nm 1-NAA, Col-0 versus 300 nm 1-NAA, arf7-1;arf19-1. Distributions of relative nuclear position are plotted; n = 150 cells per genotype or treatment. Significances of differences between distributions were determined independently for distribution along the apical-basal axis as well as for distribution along the inner-outer axis employing a nonparametric, two-sample Kolmogorov-Smirnoff (KS) test with a significance threshold of P < 0.05. **, P = 0.000. Exact P values are shown in Supplemental Table S1.