Fig. 3: Auxin signalling is required for GA to affect xylem development.
From: Gibberellins promote polar auxin transport to regulate stem cell fate decisions in cambium
a,b, Expression of DR5v2:erRFP in the root cambium after a 48 h GA treatment in 14-day-old seedlings of WT Col-0 (a) and ga1 (b). White arrowheads indicate the most recent cell divisions. The numbers −2, −1, 1 and 2 indicate the relative position of the cells in respect to the most recent cell division, with negative values towards the xylem and positive towards the phloem. c, Counts of the position in the cambium at which the DR5v2:erRFP gradient ends. Cellular positions on the x axis correspond with the cellular position in a and b. d, Comparing the DR5:erRFP gradient in WT and ga1. e, qRT–PCR analysis of the AtHB8 expression level in WT and ga1 backgrounds. f, Root cross-sections after a 6 day GA treatment in 4-day-old seedlings of Col-0, arf7,arf19 and amiMP,arf7,arf19. g, Quantification of the number of secondary xylem vessels in plants shown in f. h, Root cross-sections after a 6 day induction and GA treatment in 4-day-old seedlings of p35S::XVE»mir165a. i, Quantification of the number of secondary xylem vessels in plants shown in g. Two-tailed chi-square test in c and d; two-tailed t-test in e; Kruskall–Wallis test with Bonferroni adjustment in i. The boxes in the box-and-whisker plots in e, g and i show the median and the interquartile range, and the whiskers show the total range. Individual data points are plotted as purple dots. Numbers in g and i indicate number of samples. Boxes not sharing a lower-case letter in the plots indicate a significant difference, P < 0.05. NS, not significant. p, phloem; x, xylem; v, secondary xylem vessels. n refers to the total number of observations. Scale bars, 10 µm (a and b) and 20 µm (f and h). g was repeated four times and all other experiments three times.
