Nicotinic Acid and the Inhibition of Growth by Auxin

Abstract

IN a recent paper, Galston¹ has shown that βindoleacetic acid, at concentrations of 1–10 p.p.m., inhibits the growth in the dark of excised stem tips of Asparagus, in contrast to its normal stimulating effect in the light. Nicotinic acid, at a concentration of 0.5 p.p.m., was shown greatly to augment this dark inhibition, although without any effect by itself. These results were regarded as indicating that nicotinic acid is involved in the growth-regulating action of β-indoleacetic acid.