Plant hormones are chemical messengers that regulate plant growth, development, and responses to stimuli. Also known as phytohormones, these substances operate in very low concentrations but have a profound impact on plant physiology.
They include several major classes, among which auxins (like Indole-3-acetic acid), gibberellins, cytokinins, ethylene, and abscisic acid are most significant.
- Auxins: Key for growth directionality and cell elongation.
- Gibberellins: Important in seed germination, flowering, and stem growth.
- Cytokinins: Promote cell division and expansion.
- Ethylene: Influences fruit ripening and leaf abscission.
- Abscisic Acid: Plays a role in stress responses and seed dormancy.
These hormones often work synergistically or antagonistically to maintain plant homeostasis and adapt to environmental changes. Crosstalk among hormones fine-tunes these responses, ensuring plants grow properly and survive various stress conditions.