Recovery of labeled ribonucleic acid following administration of labeled auxin to green pea stem sections.

Recent experinm,ents with vertebrates (14, 17. 21. 36), insects (6, 10) and plants (2. 18. 19, 26, 28, 34) have shown that RNA and protein synthesis are involved in the action of a wide variety of hormones. In particular, the blockage of hormone action by low concentrations of the RNA polymerase inhibitor, actinomycin D, indicates a connection between hormone action and the de novo synthesis of nucleic acids. It thus appears that the problem of explaining the molecular mechanisms involved in initial hormone action could be attacked by a study of the detailed mechanisms connecting hormones with nucleic acid metabolism. Previous work from this laboratory (12. 16) has shown that a partial oxidation of the plalnt growth hormone indole-3-acetic acid (IAA) can complex in vitro with RNA extracted fromii growinig pea stem segments. This finding led us to inquire whether. similar complexes between auxin miietabolites alld niucleic acids could be formed in vivo.