Studies of Carboxyl-C14-Labeled 3-Indoleacetic Acid in Plants

Abstract

The rate of the absorption and translocation of C14 after receiving IAA-1-C14 (IAA) treatment on the primary leaf was studied in kidney bean plants. Only 10 to 14% of the C14 activity was transported to the other plant parts during 14 days experimental period. A larger portion remained in the treated leaf. The amount of total recovery of C14 decreased with time. Part of the applied IAA had been metabolized and the radioactivity appeared in the respiratory CO2. The effect of light on the destruction of IAA was studied in vivo in kidney bean, pea and corn plants. The destruction of IAA was greatly inhibited in the dark as measured by the production of respiratory C14O2. The bean and pea plants destroyed IAA but at a slower rate during the 12-hour period in the dark. The destruction of IAA in the corn plant was completely light-dependent. In vivo study of the effect of 2,4-D on the destruction of IAA in both bean and corn plants has been demonstrated. 2,4-D treatment decreased the rate of destruction of IAA in both plant species.