Fig 4. The effect of the Al-treatment on root system parameters evaluated after 1- day and 7 days of the exposition.

Tested Al³⁺ doses consisted of: 10; 20; 30 μM AlCl₃, in full Hoagland’s medium, pH = 4 (treatments), pH = 6 (control). The measured parameters include: total root length (A), total root area (B), total root volume (C), average root diameter (D). Different letters above the bars indicate statistically significant differences (ANOVA; p < 0.05) between combinations. The percentages above the bars indicate the reduction/ increase of the value in comparison to the control.