Cytokinins

• Cytokinins have specific effects on cytokinesis, and were discovered as kinetin (a modified form of adenine, a purine) from the autoclaved herring sperm DNA
• Kinetin does not occur naturally in plants
• Search for natural substances with cytokinin-like activities led to the isolation of zeatin from corn-kernels and coconut milk
• Natural cytokinins are synthesised in regions where rapid cell division occurs (root apices, developing shoot buds, young fruits etc)
• Cytokinin helps to produce new leaves, chloroplasts in leaves, lateral shoot growth and adventitious shoot formation
• Cytokinins help overcome the apical dominance
• Cytokinins promote nutrient mobilisation which helps in the delay of leaf senescence