Fig. 3.

The effect of NPA on the intracellular accumulation of [³H]NAA in tobacco BY-2 cells treated with 1-NOA or 2-NOA. In-flight application of NPA (10 μM) to cells treated with 1-NOA (10 μM) (A) had very low impact on the accumulation of [³H]NAA (2 nM). In-flight application of NPA to cells treated with 2-NOA (10 μM) (B) increased auxin accumulation, suggesting that auxin efflux carriers were still active before NPA treatment (note also the higher absolute values of auxin accumulation in the case of 1-NOA in contrast to 2-NOA even before NPA treatment). Error bars represent SE (n=4). (C) Effects of the auxin influx and efflux inhibitors 1-NOA, 2-NOA, and NPA on intracellular accumulation of [³H]NAA in cells treated with the inhibitor of vesicle trafficking BFA. 2-NOA did not change the accumulation of [³H]NAA in cells treated with BFA, while both NPA and 1-NOA increased it. Values are percentages of control at 20 min after application of [³H]NAA and inhibitors. Error bars represent SE (n=4).