1. A naturally occurring organic compound produced by plants that regulates growth, development, and physiological processes.
Usage: Also called plant hormone.; Technical/scientific term commonly used in botany and plant biology.

Examples

• Auxins are phytohormones that promote cell elongation and root development.
• The plant's response to light is mediated by phytohormones called phototropins.
• Gibberellins are phytohormones that regulate seed germination and stem growth.
• Ethylene, a gaseous phytohormone, triggers fruit ripening in many plants.
• Cytokinins are phytohormones that delay leaf senescence and promote cell division.
• Scientists study phytohormones to understand how plants adapt to environmental stress.
• The balance of different phytohormones determines whether a plant flowers or remains vegetative.