Distribution of nutrient elements along the maize leaf: Alteration by iron deficiency

Distribution of ten elements along the maize leaf and the effect of iron (Fe) deficiency on these distributions were studied using plants grown in nutrient solution. In both the control and Fe-deficient leaves, the concentrations of Fe, calcium (Ca), magnesium (Mg), manganese (Mn), zinc (Zn), and boron (B) increased and only that of potassium (K) decreased from leaf base to the leaf tip. Nitrogen (N) and copper (Cu) were the only two elements which showed no gradient of concentration along the entire leaf. Iron deficiency decreased the concentration of Fe by the same extent along the entire leaf length. However, it differentially accentuated the uneven distribution of some elements along the leaf length. For example, Fe deficiency increased the concentrations of Cu and N somewhat uniformly along the whole length the leaf; those of P and K were increased only along the lower two-thirds of the leaves; and those of Ca, Mg, B, Zn, and Mn mostly along the upper one-half to one-third of the leaf length. Potassium was the only element whose concentration was lower at leaf tip than at the leaf base under both Fe-sufficient and Fe-deficient conditions. My results indicate that the basal half of maize leaf may be a more suitable part for diagnostic purposes since the concentration of most elements is less subject to alteration in this region, especially if a latent or obvious Fe deficiency is present. In view of these observations, the use of the entire maize leaf for diagnostic purposes may have to be reevaluated.