Cytokinin
/ˌsaɪtoʊˈkaɪnɪn/
Definition
Cytokinin refers to a class of plant hormones, or chemical signals, that regulate cell division and influence shoot formation, bud growth, leaf aging, and nutrient movement. Produced mainly in roots and developing tissues, cytokinin moves through the plant and often acts in balance with auxin, another hormone. That hormone balance helps determine whether tissues form shoots, roots, or undifferentiated cells during growth and development.
Role and Significance
- Cell division and shoot formation: cytokinin helps drive cell division in growing tissues and strongly supports shoot initiation, especially in buds and tissue culture systems.
- Balance with auxin: Its effects depend on its ratio with auxin, another plant hormone. Higher relative levels often favor shoot development, while lower relative levels tend to support root formation.
- Delay of leaf aging: It can slow leaf senescence, the natural aging process, by helping maintain chlorophyll and protein activity in older leaves for longer.
- Movement from roots to shoots: Much of it is produced in roots and transported upward in the xylem, linking root activity with shoot growth and branching above ground.
- Use in propagation labs: In micropropagation, carefully adjusted amounts are used to stimulate new shoots from small pieces of plant tissue, which helps multiply plants under sterile conditions.
Related Terms
Auxin
Auxin is a class of plant hormones that regulate growth and development. Produced mainly in shoot tips and young…
Gibberellin
Gibberellin is a class of plant hormones, also called growth regulators, that control key stages of development. They…
Ethylene
Ethylene is a gaseous plant hormone, meaning a chemical signal that helps regulate growth and development. Plants…
Apical dominance
Apical dominance describes a plant growth pattern in which the terminal bud at the shoot tip suppresses the growth of…
Meristem
Meristem is plant tissue made of undifferentiated cells that keep dividing to produce new cells. It is the source of…
Cell differentiation
Cell differentiation is the biological process by which unspecialized plant cells develop into cells with specific…
Bud
Bud refers to a compact, undeveloped plant structure that contains embryonic tissue capable of growing into a leaf…
Terminal bud
Terminal bud refers to the bud at the very tip of a stem or shoot. It contains the shoot apical meristem, a region of…