The HCl was added to the nutrient solution to simulate the effects of acidity. The alu- minium treatment (pH 3.5 + Al) was induced by adding 1.0 mM of
AlCl3 •6H2 O. The acid treatments (pH 3.5 and pH 3.5 + Al) initialized
14 days after transplanting. All nutrient solutions were prepared
using de-ionized water.