Figure 2.

The responses of three auxin-resistant mutants to a localized supply of KNO₃. The auxin-resistant mutants (aux1–7, axr2–1, and aux4–2) and the wild type (Col) were grown under standard low-N conditions (see Fig. 1) on segmented agar plates, and the middle segment was supplied with either 1 mM KCl (control) or 1 mM KNO₃ (localized NO₃⁻ supply). Nine days after transfer, LR lengths were measured in the top (shaded bars) and middle (filled bars) segments (13 seedlings of each line per treatment).