Nucleic acid in callus formation and in redifferentiation of callus inNicotiana Tabacum

Nowadays, the biological action of growth substances as revealed in organ formation is being studied in the field of plant physiology and biochemistry. Recently, tissue culture techniques have been applied to the systems of dedifferentiation and redifferentiation of organ. Many physiologists have long believed that plant hormones, especially auxins, may be one of the triggers of callus formation. But, as yet, there are no systematic analyses of callus induction. YAMADA et al. (1,16,17,18) found that 2,4-dichlorophenoxyacetic acid (2, 4-D) and indole-3-acetic acid(IAA), so called auxins, are triggers of callus induction in mono- and dicotyledonous plants and that kinetin enhanced callus division in co-operation with auxin from the tissue of the plant. In organ formation from tobacco, SKOOG et al. (15) found in tissue culture, by a synthetic medium, that quantitative interaction between IAA, kinetin and other factors provide for cell enlargement and organ formation. Many laboratories have attempted organ formation from callus by using the same media as that which SKOOG established. They also obtained redifferentiated buds and roots, and restored tobacco plants.