2.2. Hydroponic Conditions Nutrient solutions were prepared in deionized water at the following final concen- trations: KNO3 5 mM; Ca (NO3)2 4H2O 5 mM; KH2PO4 2 mM; MgSO4 1.5 mM; Fe-EDTA 268.8 µM; MnSO4, H2O 8.9 µM; ZnSO4, 7H2O 1.7 µM; CuSO4, 5H2O 1.0 µM; H3...