Answer: Cytokinins promote cell division and delay senescence; they are used in tissue culture and to keep produce fresh.
Physiological effects:
- Promote cell division (cytokinesis) in the presence of auxin and help cell enlargement.
- Induce formation of new shoots (morphogenesis); a high cytokinin : auxin ratio favours shoot formation.
- Overcome apical dominance and promote growth of lateral buds.
- Delay senescence (Richmond–Lang effect) by promoting nutrient mobilisation and protein synthesis, keeping leaves green longer.
- Help break dormancy of some seeds and promote chloroplast development.
Applications: used in plant tissue culture to induce cell division and shoot formation in callus; sprayed to keep cut flowers, vegetables and leafy greens fresh for a longer time; used to increase shelf life and to promote branching.
