The Use of Radioactive Phosphorus in Translocation Studies

Abstract

A difficult problem in the study of rapid solute movement in plants is to limit the solute to a single conducting tissue. Methods are described whereby the rapid longitudinal movement of radioactive P can be limited to the phloem and can be studied by means of radioautographs and the Geiger counter. Studies on the rate and direction of transport and upon the localization of radioactive P under various conditions show that when this indicator is restricted to the phloem its movement is correlated with food movement in the plant.