Figure 1.

Effects of decapitation and NPA on auxin efflux from node 5 axillary buds into the main stem. A, Pea plants with seven leaves fully expanded were decapitated (decap) 10 mm above node 5 (A, right). Treatment site and region were sampled for [³H]IAA quantification. Three hours after decapitation, node 5 axillary buds were treated with 0.25 μL of [³H]IAA alone or in solution with 1 mm NPA. Two hours after treatment, internode tissue 3 to 27 mm below node 5 was sampled in 3-mm segments and quantified for radioactivity. B, Total [³H]IAA exported out of buds; different letters (a, b) on the top of the columns indicate statistically significant differences (P < 0.05; one-way ANOVA with Tukey’s correction). C, [³H]IAA exported out the buds as quantified in adjacent 3-mm stem segments. Data are means ± se (n = 3 to 6).