Effects of Herbicides on RNA and Protein Syntheses

Abstract

Effects of 22 herbicides on the synthesis of RNA and protein were investigated in excised tissues. The assays measured ATP and orotate incorporation into RNA, leucine incorporation into protein, and the gibberellin-controlled induction of a-amylase Statistical analysis of the average responses measured in the four assays suggested that 14 of the herbicides inhibited RNA and protein biosyntheses in vivo. The most inhibitory chemicals were 4-hydroxy-3,5-diiodobenzonitrile (ioxynil), 2- sec -butyl-4,6-dinitrophenol (dinoseb), 3',4'-dichloropropionanilide (propanil), 2,3,5-trichloro-4-pyridinol (pyriclor), and isopropyl m -chlorocarbanilate (chlorpropham). The activity of an RNA polymerase isolated from corn (Zea mays L.) tissue was inhibited maximally at approximately 20% by ioxynil, dinoseb, and pyriclor. Hence, interference with RNA polymerase, which performs a pivotal role in RNA and protein biosyntheses, does not fully account for all inhibitions.