KINETICS AND TRANSLOCATION OF PHOSPHORUS IN MAIZE HYBRIDS

The objective of this work was to study the P absorption and P translo cation in maize (Zea mays, L.) hybrids, grown at two P levels. Plants of three maize hybrids grown in nutrient solution with 0.02 mM and 0.1 0 mM of P were submitted to a P depletion experiment and to a P transl ocation experiment. The kinetic parameters (Imax, Km and Cmin), the we ight and the P content of xylem exudate, and the P translocation from roots to shoots were evaluated. The reduced P level in nutrient soluti on increased Imax but without changes in Km e Cmin. Phosphate starvati on decreased the weight and the P content of xylem exudate and the P t ranslocation from the roots to the shoots in all hybrids. The hybrid B R 201 showed higher net influx rate, Imax and P content in xylem exuda te at low P level when compared with the other hybrids.