Figure 3.

Relationship between the rate of citrate exudation and Al resistance, as measured by RRG. The two sections on the left show the citrate exudation rates [estimated between days 1 and 2 (top section) and days 3 and 4 (bottom section)] and RRG for the six maize genotypes exposed to 20 μm Al³⁺ activity. The two sections on the right show the citrate exudation rates [estimated between days 1 and 2 (top section) and days 3 and 4 (bottom section)] and RRG for the six maize genotypes exposed to 40 μm Al³⁺ activity. RRG values and exudation rates correspond to those shown in Figure 1 and Table I, respectively. Horizontal and vertical bars indicate the SEM. The numbers refer to the different maize genotypes in order of decreasing Al resistance: highly Al-resistant Cateto-Colombia (no. 1), moderately Al-resistant Pioneer (no. 2), and Al-sensitive Mo17 (no. 3), B73 (no. 4), L53 (no. 5), and 11 × 723 (no. 6).