Sur l'action de l'acide 2,4-dichlorophénoxyacétique sur la croissance des racines deZea mays et dePisum cultivéesin vitro

Summary

(1) A response ofZea mays andPisum roots cultured aseptically to 2,4-dichlorophenoxyacetic acid has been observed.

Depending on the concentrationZea mays shows an increase of the growth rate (optimal concentration 10⁻¹¹ mol) which turns over to an inhibition (above 10⁻⁷ mol). The curve is similar to that obtained by 3-indoleacetic acid, which proves the phytohormonal character of 2,4-D.

(2) ThePisum root is more sensitive than theZea mays root. A concentration of 10⁻⁷ molinhibitsPisum in a high degree, whileZea mays is no more inhibited, thus demonstrating the selective herbicidal action of 2,4-D against isolated roots of Dicotyledons culturedin vitro.