Cytokinins are a group of plant hormones primarily involved in promoting cell division and regulating plant growth and development.
Physiological Effects of Cytokinins
1. Regulation of Cell Cycle:
Cytokinins play a key role in controlling the cell cycle, particularly in stimulating the transition from the G2 phase to mitosis, ensuring balanced cell division.
2. Regulation of Morphogenesis:
They influence organ formation, determining whether a callus (undifferentiated cell mass) develops into roots or shoots, depending on cytokinin-to-auxin ratios.
3. Delay of Senescence:
Cytokinins slow down the aging process in leaves by maintaining protein synthesis, chlorophyll levels, and cellular integrity, extending leaf life.
4. Promotion of Lateral Buds Development in Dicots:
Cytokinins overcome apical dominance by promoting the growth of lateral buds, enabling bushier plant growth in dicot species.
5. Promotion of Chloroplast Maturation:
They aid in the development and maturation of chloroplasts, enhancing photosynthesis efficiency in plants.
6. Stimulation of Cell Enlargement:
Cytokinins promote cell enlargement by increasing cell wall plasticity and water uptake, contributing to overall plant growth.
Significance of Cytokinins
Cytokinins are essential for coordinating growth and development, delaying senescence, and improving plant resilience, making them vital for agriculture and horticulture.