Cytokinins are phytohormones mostly responsible for cell division. Carlos Miller et.al. In 1955 for the first time isolated a “cell-division stimulating-factor” from Yeast and named it as kinetin.
Kinetin has amazing power to stimulate cell division in presence of auxin. All such compounds responsible for stimulation of cell division have been grouped under a generic name Kinin (Miller 1956).
Leetham in 1963 proposed the name cytokinins. Zeatin is a naturally occurring cytokinin in maize. Cytokinins are produced in roots and probably originate at the root tips and are translocated to aerial parts through the xylem. Chemically kinetin is 6-furfuryl amino purine.
1. Induce cell division in presence of auxins.
2. Besides auxins and gibberellins cytokinins also promote cell elongation.
3. Cytokinin is capable of stimulating as well as inhibiting root development.
4. Help in breaking seed dormancy.
5. Kinetin counteracts apical dominance.
6. Delay senescence, influence growth and development and influence abscission. This senescence retarding effect is known as Richmond-Long effect named after the discoverers.