Ethylene
Ethylene is a small, gaseous plant growth regulator that is produced in large amounts by tissues undergoing senescence and ripening fruits. Its synthesis has critical physiological effects throughout the plant lifecycle. Its known influences include:
- Growth Regulation: Ethylene promotes various types of growth, including horizontal growth of seedlings and swelling of stems.
- Senescence and Abscission: It significantly influences the aging process in plants, contributing to the senescence of leaves and flowers and the detachment of these organs from the plant through abscission.
- Fruit Ripening: Ethylene is best known for its role in the ripening of fruits, enhancing respiration rates during ripening, which is termed as the 'respiratory climactic'.
- Dormancy Regulation: Ethylene helps break seed and bud dormancy, initiating germination and sprouting in various plants.
- Flood Response: In deep-water rice plants, ethylene promotes rapid internode elongation, assisting plants to grow above water surfaces for better light access.
- Agricultural Applications: Ethylene is extensively used to facilitate fruit ripening and induce flowering in crops like pineapples and mangoes. The compound most commonly utilized as a source of ethylene in agriculture is ethephon, which releases ethylene over time when introduced to plants.
As a result of these functions, ethylene is a vital tool in both horticultural and agricultural practices.