Fig. 5.

Al content in 1 cm root tips of Al-sensitive common bean genotype (VAX 1). (A) Without dialysis membrane tubes (DMT); plants were pre-treated without or with 150 g l⁻¹ PEG solution for 8 h, and then treated with 25 μM Al in the absence or presence of 150 g l⁻¹ PEG solution for 1 h. (B) With DMT; plants were pre-treated without or with 200 g l⁻¹ PEG for 8 h, then treated with 100 μM Al in the absence or presence of 200 g l⁻¹ PEG solution for 1 h. (C) Without DMT; plants were pre-treated without or with 150 g l⁻¹ PEG solution for 8 h, and then treated with 25 μM Al solution for 15, 30 and 60 min. The background solution of the above treatment solution was the simplified solution containing 5 mM CaCl₂, 1 mM KCl, and 8 μM H₃BO₃, pH 4.5. –/– PEG: without PEG during pre-treatment and Al treatment; +/– PEG: with PEG during pre-treatment, without PEG during Al treatment; –/+ PEG: without PEG during pre-treatment, with PEG during Al treatment; +/+ PEG: with PEG during pre-treatment and Al treatment. 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 pre-treatments within PEG re-treatments and comparison of PEG re-treatments within PEG pre-treatments, respectively.