Figure 4.

Blue light-inhibition of ABCB19 increases auxin levels in petioles. A, Quantification of DII-VENUS signal on the petiole underside of the first pair of true leaves near the petiole-hypocotyl junction in Col-0 and abcb19 after 3 d under 50 m⁻² s⁻¹ red plus far-red (50R + FR), 50 m⁻² s⁻¹ red (50R), or red plus 5 m⁻² s⁻¹ blue light (50R + 5B). Seedlings were grown as in Figure 1. Background signal was subtracted using Col-0 grown under equivalent conditions. Data shown are means ± se (n = 8–10). Asterisks indicate statistical difference by two-way ANOVA (P < 0.0001), followed by Dunnett’s post-hoc (*P < 0.05), versus Col-0 for each condition. B, Schematic of Col-0 and abcb19 depicting position of DII-VENUS imaging (red box) used in A. C, Representative images of DII-VENUS signal in Col-0 and abcb19 in A. Scale bar = 100 µm.