Effect of 4-Amino-3,5,6-trichloropicolinic acid on Protein Synthesis

The effects of 4-amino-3,5,6-trichloropicolinic acid (picloram) on protein synthesis in bean (Phaseolus vulgaris L. cv. ‘Astro’) hypocotyl and hook tissues were studied. Picloram (10^-4M) was shown to have a stimulatory effect on ¹⁴C-1-DL-leucine uptake in hook but not hypocotyl tissues. Maximum leucine incorporation and maximum total protein concentration occurred in hook tissues treated with 10^-4M picloram. Inhibition of protein synthesis with cycloheximide (CH) and erythromycin (ERY) indicates that endogenous and picloram-stimulated protein synthesis is a function of the 80S cytoplasmic ribosomes rather than 70S chloroplast or mitochondria ribosomes.