Figure 2.

Auxin Mediates the Al-Induced Inhibition of Root Growth.

(A) to (C) Effect of exogenous NAA on root growth following a 7-d exposure to 0 or 2.5 nM NAA in the presence of 0 to 6 μM AlCl₃ ([A] and [B]) or 0 to 5 nM NAA in the presence of 0 or 5 μM AlCl₃ (C). Asterisks in (B) and (C) indicate that NAA treatments differ significantly at *P < 0.05, **P < 0.01, and ***P < 0.001 (t test).

(D) to (F) Root growth after a 7-d exposure to AlCl₃. Wild-type plants and gain-of-function mutants slr-1, PIN8 OX, and yuc1D were exposed to 0, 4, 6, or 8 μM AlCl₃. Asterisks indicate that means within the wild type and slr-1, PIN8 OX, or yuc1D in each Al concentration differ significantly at *P < 0.05, **P < 0.01, and ***P < 0.001 (t test).

Values in (B) to (F) represent means ± sd (n = 30).

[See online article for color version of this figure.]