1. Cytokinins are growth promoting hormones that stimulate cell division.
2. Skoog and Miller discovered first cytokinin when they were investigating nutritional requirements of tobacco callus culture.
3. It was observed that the callus proliferated when there was addition of coconut milk as supplement.
4. The degraded sample of herring (fish) sperm DNA also showed similar growth of tobacco callus. They named the substance as kinetin.