Marcelo Kogan A.1, Takashi Muraoka2, Virgilio F. Nascimento Filho2 y André M. L. Neptune3

Exised roots from barley (Hordeum vulgare, L.), obtained through the Epstein and Hagen technique, were placed in flaks containing 50 ml of 10-4 M KH2PO4 solution, with activity of 3u Ci 32P and different concentrations of 2,4-D: 0 - 1 y 10 ppm. Measurements of the activity of the roots were taken 15, 30 and 60 minutes after the experiment was started. A marked decrease in the absorption of phosphorus by the roots in presence of 2,4-D wasobserved.

1Ing. Agr., M. S., Profesor Control de Malezas, Facultad de Agronomía, Universidad de Chile.
2Ings. Agrs., Becarios del Centro Nacional de Energía Nuclear, Brasil.
3Ing. Agr., Dr. Profesor de Disciplina del Departamento de Suelos y Geología de la Escola Superior de Agricultura "Luz de Queiroz", São Paulo, Brasil.