What does phytochrome mean?
A phytochrome is a light-sensitive protein used by plants and algae to detect particular wavelengths of light, especially red and far-red light. Its name reflects its original association with plant responses to light and color. Phytochromes change between two interconvertible forms: one that absorbs red light and one that absorbs far-red light. This reversible system helps plants respond to environmental conditions. It can influence seed germination, the growth of seedlings, the avoidance of shade, and the timing of flowering. When a plant is shaded by other vegetation, the light quality changes, and phytochrome signaling can help the plant adjust its development. In this way, phytochromes allow plants to use light not merely as an energy source but also as information about their surroundings.
nounA light-sensitive protein found in plants and algae that detects red and far-red light and regulates plant responses such as germination, shade avoidance, and flowering. Phytochromes function by reversibly switching between red-light-absorbing and far-red-light-absorbing forms.
- A photoreceptor protein that detects red and far-red light in plants and algae.
- The broader signaling system involving phytochrome proteins and the cellular responses they regulate.
"The seedlings developed elongated stems when their phytochrome system detected that they were growing in shade."
"Phytochrome activation helped the seedlings recognize that neighboring plants were shading them."
"Researchers studied how phytochrome influences flowering in response to the length of the day."
Used when referring to multiple members of the phytochrome family or to multiple distinct phytochrome proteins.
"Different phytochromes can control overlapping aspects of plant development."
Plants can effectively measure the color of light, allowing phytochromes to tell whether they are in sunlight or shade and adjust their growth accordingly.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does phytochrome come from?
The word phytochrome combines Greek roots meaning “plant” and “color,” reflecting the compound's association with plant responses to colored light. The underlying English terms are also found in words such as photosynthesis, phytolith, and phytoplankton. Phytochrome belongs to the scientific vocabulary of plant physiology, where the name distinguishes this particular class of light-sensitive proteins from other photoreceptors.
How phytochrome is actually used
In technical biological writing, phytochrome most often refers to the family of photoreceptor proteins. The term is specialized and is not normally used in general conversation.