Al was added to the Hoagland solution and was supplied in the
form of AlCl3$6H2O in concentrations of 0 [this is the control check
(CK)], 10, 30, 60 and 90 mg L1 for 14 days. The nutrient solution
was adjusted to pH 4.5 0.05 by HCl and NaOH and was renewed
every five days. After 14 days of treatment, the plants measured
about 30 cm in height and had an average of eight leaves. The plants
were then removed from the nutrient solution and the roots were
carefully washed with double-distilled water in preparation for use
in further analysis.