Effects of Nitrogen and Phosphorus Nutrition on [14C]-Sucrose Translocation in Hibiscus esculentus

Abstract

Summary The influence of nitrogen (N) and phosphorus (P) nutrition on the retention of [14C]-sucrose by fed leaves and the distribution patterns of 14C were investigated in vegetative okra plants at the 4-leaf stage. When the oldest leaf 1 was fed, medium and high levels of N and P (20 and 200 mg/1, compared with 2 mg/l) enhanced the outflow of assimilates in a 48 h period. High levels of N enhanced [14C]-distribution to the leaves but decreased that to the stem and the root. The high level of P decreased the distribution to the leaves but enhanced that to the root. When the youngest leaf 4 was fed, high levels of N again enhanced while high levels of P decreased 14C export. The high level of N generally had no significant effect on 14C distribution patterns. The high level of P decreased 14C distribution to leaves, at it did when leaf 1 was fed, but decreased that to the stem while it had no significant effect on 14C imported by the root. The effects o N were, therefore, generally opposite to those of P in terms of both the distribution of 14C to the leaves, stem and root, and the direction of transport.