Synthetic auxins are currently used to promote adventitious root formation and thereby propagation by cutttage of plants in horticulture. In the present study, we tested commercial products, named NSC-Base® and NSC-Pro®, which are alkaline hydrolysis products of soy oil and pine seed oil, respectively, for possible use as agents to promote adventitious root formation. The commercial products were found to stimulate adventitious root formation in cut stems of ornamental cabbage, and in root-cut seedlings of mung bean, cucumber, sweet pepper, tomato, melon and pumpkin. Their root-forming activity was further characterized using NSC-Base® and mung bean seedlings. NSC-Base® is mainly composed of sodium salts of long chain fatty acids. NSC-Base® diluted to 104 to 102 times and sodium linoleate, the major ingredient of NSC-B®, at 0.1 and 1.0 mM, significantly increased adventitious root formation, when judged by the total root length and number of roots. Among sodium salts of long chain fatty acids included in NSC-Base®, sodium salts of unsaturated fatty acids, linoleic acid, linolenic acid and probably oleic acid at 1 mM, were active in promoting adventitious root formation, but those of saturated fatty acids were not. Simultaneous application of NSC-Base® with 3-pyridinecarboxylic acid, a stimulator of root elongation, exerted a synergistic effect on root elongation in root-cut mung bean seedlings.
