Cytokinins - Plant Growth Substances

Folke Skoog observed that the cell division or differentiation is affected by AMP and other purines. A nucleic acid from yeast was also found to be useful or effective. Isolation efforts from yeast t-RNA using the differentiation of tobacco tumor cultures as a bioassay have lead to the discovery of kinetin or 6-furfury aminopurine. Lethan and others isolated another cytokinin zeatin from corn plants. Today, we know quite a few types of natural and synthetic cytokinins. We call them cytokinins because they essentially promote cell division. Other effects of cytokinins are retardation of senescence, development of buds in moss protonema, release of inhibiters from buds.