Cytokinin

• First endogenous cytokinin was isolated from maize kernels named as zeatin.
• Germinating seeds, roots, sap streams, developing fruits and tumor tissue are rich in cytokinins.
• Cytokinins imbibed seeds germinate better in dark than unimbibed lettuce seeds.
• Similarly cytokinin together with gibberllin effectively breaks the photodormancy of celery (Apium graveolens) seeds.
• Synthetic cytokinins are kinetin, benzyladenine and ethoxy ethladenine.

Role of cytokinin

• Cell divisions, elongation and enlargement       
• Induction of flowering, fruit development    
• Apical dominance-overcoming                              
• Delay senescence   
• Tissue culture morphogenesis
• Parthenocarpy
• Breaking dormancy            
• Improves N2 metabolism

Cell division	Auxillary growth	Delaying of senescence