Spraying of Barley with 2,4-Dichlorophenoxyacetic Acid

Abstract

DR. H. INGVARD PETERSEN has discovered differences in the translocation of the plant growth regulator herbicides applied to cereal plants of different ages¹. His autoradiographs show that whereas radioactive 2,4-dichlorophenoxyacetic acid applied to barley at the one- to three-leaf stage is readily translocated to all parts of the plant, including, presumably, the growing point, application to successively older plants results in progressively less translocation. This plant growth regulator herbicide applied to the fifth and sixth leaves of a five- to six-leaf plant appears to be translocated to a very limited extent indeed.