Effect of Nitrogen on Phosphorus Transport Systems in Zea Mays L.

The effect of N preconditioning on P uptake and translocation was studied using 10‐day‐old corn ( Zea mays L.) in solution culture. Nitrogen preconditioned plants had significantly higher P uptake rates and translocation. Plants remained capable of stimulated P absorption and translocation for periods dependent upon the time interval between N pretreatment and P uptake. The degree to which P uptake was stimulated was dependent upon the N level used for preconditioning. A rather low level, 4m M , resulted in maximum increase in P uptake over control plants. Phosphorus transport to the upper part of the plant increased as N levels in the pretreatment increased. Nitrogen preconditioning stimulated P uptake and translocation maximally when P was supplied at 0.1m M . At lower concentrations only uptake was stimulated while at higher levels, only translocation was stimulated. Observations suggest involvement of more than one P uptake mechanism and separate physiological influence of N on uptake and translocation.