Inhibition by p-Fluorophenylalanine of Protein Synthesis and of Ion Transport Across the Roots in Barley Seedlings

Abstract

The transport of ions across the plant root can be inhibited by cytokinins, abscisic acid and cycloheximide. It appears that secretion of ions into the xylem vessels is a different kind of process from active transport into the cortical cells, as it is not affected to the same extent by these compounds.

In the present paper it is shown that p-fluorophenylalanine (FPA) also inhibited transport across the root without reducing uptake to the cells, and hence it is concluded that transport involves a specific protein. From the time needed to produce inhibition with FPA it appears that this protein has a short effective life.

Measurement of distribution of ³⁶Cl between stele and cortex showed that these inhibitors did not stop movement of ions into the stele. It seems then that the site of action of the proteins is within the stele, probably between xylem parenchyma and xylem vessels.