Fig. 4.

[¹⁴C]tZ tracer experiment and xylem sap assays in the wild type and osabcg18 mutant. Radioactivity in shoots (A) and roots (B) of the wild type and osabcg18 mutant 20 h after feeding [¹⁴C]tZ to the roots. Seedlings grown in hydroponic conditions were used. The transport of exogenously applied [¹⁴C]tZ from roots to shoots was significantly suppressed in osabcg18 mutant. Data are means ±SD (n=5). (C) Cytokinin profiling in xylem sap from the wild type and osabcg18 mutants. tZ, tZR, cZ, cZR, iP, and iPR were measured. Data are means ±SD (n=3). *P<0.05 and **P<0.01 (t-test in one-way ANOVA). tZ, trans-zeatin; tZR, trans-zeatin riboside; cZ, cis-zeatin; cZR, cis-zeatin riboside; iP, isopentenyladenine; iPR, isopentenyladenosine.