Magnesium Absorption and Utilization by Two Inbred Lines of Corn

Certain corn inbred lines are known to differ widely in the magnesium accumulating abilities of their leaves. The purpose of this investigation was to test the hypothesis that such differences in “magnesium feeding power” can be explained by differences in root properties. Corn inbred lines Indiana WF9 (high leaf magnesium) and Ohio 40B (low leaf magnesium) were selected for comparison. Results indicate that low levels of magnesium in Ohio 40B leaves were not due to any lack of magnesium ad sorbing or ab sorbing ability on the part of roots of this plant. Roots of Ohio 40B had a higher total cation‐exchange capacity and adsorbed magnesium more rapidly from solution than did those of Indiana WF9. Ohio 40B leaves were always lower in magnesium content than those of Indiana WF9 whether plants were grown in sand culture or soil. Stems of Ohio 40B plants contained a higher percentage of magnesium than did those of Indiana WF9, and this magnesium was more difficult to extract with 1 N ammonium acetate. It is concluded that the low concentration of magnesium in Ohio 40B leaves is due, primarily, to an immobilization of magnesium in the stems of this plant.