Fig. 1.

Effect of increasing Al concentrations on the signal grass root elongation rate (RER) during 120 h in basal solution (Experiment 1). (A) The RER in basal solution over time when exposed to 0, 100, 200 and 1000 µm Al (nominal concentrations). (B) The RER in basal solution after 120 h growth in a control or in solutions containing one of nine measured Al concentrations. (C) Effect of Al³⁺ activity on the relative RER. Values are the arithmetic mean of two replicates, with each replicate containing seven seedlings. The vertical bars correspond to the s.d.