Studies on the Relation of Chemical Structure to Plant Growth-Regulator Activity in the Pineapple Plant. III. Naphthalene Derivatives and Heterocyclic Compounds

Abstract

1. Results of testing sixty-four naphthalene derivatives, ninety-two heterocyclic compounds, and thirteen miscellaneous materials for their effects on induction or inhibition of flowering and toxicity to the pineapple plant are given. In addition, results in the split pea-stem curvature test are listed for many of the compounds. 2. Certain esters, the ethanol, the acetamide, and the acetonitrile derived from 1-naphthaleneacetic acid, and a few further modifications of the acetic acid side chain were active in forcing pineapple plants to flower. Of the several reduced-ring compounds tested, only the cis-1,2,3,4-tetrahydronaphthylidene-1-acetic acid and 3,4-dihydronaphthalene-1-acetic acid forced flowering. Of those compounds with further substitution on the naphthalene nucleus, 2-methyl-1-naphthaleneacetic acid was the only forcing one. 3. Although, in general, compounds which forced pineapple to flower also were active in the pea test, activity in the two tests was not well correlated. Examples of compounds which forced flowering in pineapple but had low or no activity in pea tests are γ-(1-naphthyl)butyric acid and β-(1-naphthyl)-propionic acid. 4. Although indolebutyric and indoleacetic acids were active in forcing, few other heterocyclic compounds were. An exceptional compound was N-aminomorpholine, which forced; it resembles β-hydroxyethylhydrazine more closely than it does active aromatic plant growth-regulators. 5. Indoleacetic acid antagonizes the forcing effect of indolebutyric acid. This is taken as evidence that the latter forces per se rather than only after β-oxidation to indoleacetic acid. 6. Gibberellic acid was neither forcing nor inhibitory to flowering and was relatively inactive on pineapple plants more mature than seedlings.