Diuron decreases light‐stimulated potassium translocation to shoots of barley seedlings

Abstract

Abstract Guttation through passive hydathodes was used as a non‐destructive xylem sampling technique to study the effect of the herbicide diuron [3‐(3,4‐dichloro‐phenyl)1,1‐dimethyl urea] on potassium translocation in intact barley seedlings. Five‐day‐old dark‐grown seedlings were placed under light with or without 1 μM diuron in the root medium. After 48 hours, potassium was added to the root medium and the plants transferred to high humidity. Twelve hours later, guttation fluid was collected and the potassium content of roots, shoots and guttation fluid measured. Shoots of seedlings which had received light treatments contained larger amounts of potassium and had smaller amounts of potassium in their guttation fluid than dark‐grown seedlings. Diuron reduced this light‐stimulated increase in shoot potassium content and increased the amount of potassium in the guttation fluid. These results suggest that shoots of barley seedlings do modify the ionic content of the xylem sap, and that changes in the ionic ...