Ethylene is the plant hormone primarily responsible for senescence.
Senescence, the process of aging in plants, is a highly regulated and complex developmental stage involving the breakdown of cellular components. While multiple factors contribute to this process, ethylene plays a crucial role.
Ethylene's Role in Senescence
Ethylene is a gaseous plant hormone that influences various aspects of plant growth and development, including:
- Fruit ripening: Ethylene is well-known for its role in triggering and coordinating the ripening of fruits.
- Leaf abscission: Ethylene promotes the shedding of leaves, a key aspect of senescence, especially in deciduous plants.
- Flower senescence: It also induces the wilting and death of flowers.
- Increased respiration rate: Ethylene increases the rate of respiration in plants, which contributes to the breakdown of cellular components during senescence.
- Break seed and bud dormancy: While not directly related to senescence, ethylene's role in breaking dormancy can be seen as part of the plant's overall developmental cycle, which includes aging and eventual death.
Other Factors Involved in Senescence
While ethylene is a major player, other factors also contribute to senescence, including:
- Abscisic acid (ABA): ABA can also promote senescence in some plant tissues.
- Cytokinins: Cytokinins generally delay senescence.
- Light and nutrient availability: Environmental factors significantly influence the timing and rate of senescence.
However, ethylene is widely recognized as the primary hormonal regulator of senescence in many plant tissues.
