Cytokines
Stimulate cell division (with auxin) and differentiation
Discovered 1913 (G. Haberlandt, Austria): conversion of parenchyma cells to meristematic cells by coconut milk
Essential for mitosis and cell division by synthesis or activation of specific cell-division proteins
Produced in root apical meristem and transported throughout plant
Developing fruits are also sites of cytokine production
Inhibit formation of side buds (opposite to auxin) ? balance of auxin:cytokine determine shape of plant