Effect of Oxindoles on the Growth of Tobacco Tissue Cultures

Abstract

IT has been suggested that oxindoles are products of the enzyme oxidation of indolyl-3-acetic acid (IAA)^1,2, but they have generally been found to be inactive as auxins in standard auxin bioassays³. Galston and Chen⁴, however, recently reported that isatin (indole-2,3-dione) and oxindole-3-acetic acid promote the elongation of etiolated and green pea stem sections. Isatin was also found to be active in stimulating the in vitro growth of Pelargonium pith tissue—a tissue which requires an auxin for growth⁵. In light of these findings, and the fact that oxindoles do not conform to generally accepted structural requirements for auxins, it was decided to test the effect of oxindoles as auxins on another system which requires an auxin, namely, the growth of tobacco pith tissue.