Phosphorus‐zinc Interaction in Relation to Absorption Rates of Phosphorus, Zinc, Copper, Manganese, and Iron in Corn

Abstract

The effects of P and Zn on growth, nutrient content in tops and roots, and the rates of absorption of P, Zn, Cu, Mn, and Fe per unit fresh weight of roots for two growth periods of corn (Zea mays L.) were studied in soil culture under greenhouse conditions. Visual symptoms of Zn deficiency appeared in plants when the level of applied P was raised to 75 µg P/g soil. Phosphate decreased tissue‐Zn concentration and Zn flux through roots. Zinc deficient plants had higher concentration of P in their tissues. Phosphate flux was mostly reduced with Zn, but during 27–48 days growth, Zn‐supplied plants retained near identical rates of P absorption (approximately 14 µg/g fresh root/day) irrespective of the level of P supplied. The rate of Cu absorption was reduced with both P and Zn as the plants aged. Manganese flux was initially stimulated by P but later on drastically reduced by Zn. Iron concentration in plants decreased with Zn application but significant reduction in Fe flux with Zn occurred during early growth of 25 ppm P‐supplied plants only. In general, nutrient fluxes diminished with plant age.