Quantitative contribution of symplastic and apoplastic pathways to radial transport of ammonium in roots.

(A) Schematic representation of radial transport pathways in roots of tko or tko sgn3 without or with reconstituted expression of AMT1;2 (+1;2) or AMT1;3 (+1;3). (B and C) Normalized shoot accumulation as readout for radial transport rates of NH4+-N at 200 μM (B) or 4 mM 15NH4+ (C). (D and E) Estimated contribution of the ATP or the STP in absence or presence of an EB at 200 μM (D) or 4 mM 15NH4+ (E). Values were calculated by subtracting the background of tko. Bars represent means ± SD (n = 4 biological replicates). Different letters indicate significant differences according to Tukey’s multiple test at p S1 Data. 15NH4+, 15N-labeled ammonium; AMT, ammonium transporter; ATP, apoplastic transport pathway; DW, dry weight; EB, endodermal bypass; N, nitrogen; sgn3, schengen 3; STP, symplastic transport pathway; tko, amt1;1 amt1;2 amt1;3.