to study the effect of nitrogen form and ph of nutrient solution on the uptake and concentration of fe, zn, cu and mn in roots and shoots of spinach plant, a factorial experiment was conducted with two factors including nutrient solution ph in three levels (4.5, 6.5 and 8.0) and nitrate to ammonium ratio of nutrient solution in five levels (100:0, 75:25, 50:50, 25:75 and 0:100). the experiment ...