Fig. 2.

Organic acid contents in 1 cm apical roots of common bean genotype VAX 1 (Al-sensitive) affected by osmotic stress and Al supply. Plants were pre-cultured in a simplified nutrient solution containing 5 mM CaCl₂, 1 mM KCl, and 8 μM H₃BO₃ for 48 h for acclimation and pH adaptation, then treated without or with Al (25 μM) in the absence or presence of PEG (150 g l⁻¹) in the simplified nutrient solution for 4, 8, and 24 h, pH 4.5. Bars represent means ±SD, n=4. Means with the same small letter and capital letter are not significantly different at P <0.05 (t test) for the comparison of PEG treatments within Al supplies and comparison of Al treatments within PEG supplies, respectively. For the ANOVA, *^, **^, *** denote significant differences at P <0.05, P <0.01, P <0.001, respectively; ns=not significant (F test).