Absorption, retention and translocation of the systemic fungicide triarimol in plants

Only very small quantities of triarimol are exported from bean leaves to other plant organs. Triarimol is acropetally transported in the xylem sap of bean explants, however, considerable amounts of it are loosely bound in transit. The bound material is released by additional amounts of water passing through the explant. When barley roots or bean leaf slices are incubated in a medium containing triarimol the fungicide is accumulated so that much higher concentrations are present than in the medium. The retention and accumulation of triarimol by plant tissue is a nonmetabolic process resulting from weak binding to proteins. It is suggested that the translocation of triarimol in the apoplast as well as in the symplast of plants depends on the rate of water flux through the system and on the intensity of its binding.