Fig. 4.

Effect of (A) AVG, (B) Co²⁺, (C) AgNO₃, and (D) NPA on root elongation in the absence and presence of 50 μM AlCl₃ (pH 4.5). To minimize the effect of these chemical agents on Al³⁺ activity, seedlings were first exposed to 10 μM AVG (A), 10 μM CoCl₂ (B), or 10 μM NPA (D) for 2 h followed by incubation in 50 μM AlCl₃ for another 24 h. For treatment with Ag⁺, seedlings were first incubated in 10 μM AgNO₃ and then exposed to 50 μM Al(NO₃)₃ for 24 h to determine the effect of Ag⁺ on root elongation of Arabidopsis wild-type (Col-0) (C). Root elongation was expressed relative to root elongation in the control solution (0.5 mM CaCl₂, pH 4.5). Data are means ±SE of >8 roots.