Fig. 1. Correlation between Arabidopsis root waving and lateral root positioning. (A) Vertically grown Col-0 seedling with wavy growth pattern of the root. (B) Detail of boxed area in A showing the left (L) - right (R) alternating lateral roots.?, wave where lateral root is not apparent. (C) Root grown at 45° to enhance waving. Positions of lateral root primordia are marked by the CYCB1;1::GUS activity. (D) Schematic illustrating the method to determine lateral root positioning/root wave relationship. a, amplitude of the wave; b, root length between the curve tops; the red line marks the top of the wave; +, lateral roots perfectly on top of the wave; -, lateral root at the side of a wave. (E) Quantification of left-right alternation of lateral roots in vertically grown seedlings with an equal and dissimilar percentage for wild type (Col-0) and aux1-7, respectively. ^*, statistically significant difference for right side values as determined by Student's t-test (P<0.001). Error bars, s.e.m. (F) Vertically grown agravitropic aux1-7 seedling root with curled main root. The left (L) position of lateral roots is indicated.