Figure 4.

PCIB or NPA treatment to axillary buds has no effect on polar auxin transport (PATS) in the main stem. A, 0.25 μL of [³H]IAA was applied to the shoot tip of pea plants with seven leaves fully expanded and 120-mm distance between node 5 and the shoot tip. B, eleven hours after [³H]IAA application, 0.25 μL of either mock solution (100% ethanol), 1 mm NPA, or 1 mm PCIB was supplied to axillary bud on node 5. B and C, Two hours after NPA or PCIB application, internode tissue 30 mm above and below node 5 was sampled in 6-mm segments and quantified for radioactivity. B, Total [³H]IAA in the sampled stem segments; the letter “a” on the top of the columns indicates statistically significant differences (P < 0.05; one-way ANOVA with Tukey’s correction). Data are means ± se (n = 4). C, [³H]IAA in the sampled stem sections as quantified in continuous 3-mm stem segments.