1. Plural of phytochrome; photoreceptor proteins in plants that regulate growth and development in response to light, particularly red and far-red light wavelengths.
Usage: technical; biology; usually used in plural form in scientific contexts

Examples

• Phytochromes help plants detect day length and adjust their flowering time accordingly.
• The activation of phytochromes triggers seed germination in many plant species.
• Scientists study phytochromes to understand how plants sense their light environment.
• Phytochromes exist in two interconvertible forms depending on light exposure.
• The discovery of phytochromes revolutionized our understanding of plant photobiology.