What does gravitropism mean?
Gravitropism is the directional growth of a plant or other organism in response to gravity. Its best-known example occurs in roots and shoots: roots generally bend downward as they grow, while shoots generally bend upward, helping a plant establish itself in the soil and orient its growth. The process differs from phototropism, which is growth in response to light, and from hydrotropism, which is growth in response to water. Gravitropism is also distinct from simple gravitational settling or movement, because it concerns active changes in growth and orientation. The term is used mainly in plant physiology, biology, and horticulture, where it describes positive gravitropism toward gravity and negative gravitropism against it. Although the older word geotropism is still sometimes used, gravitropism is the more precise modern expression. Understanding the phenomenon is useful for studying plant development, agricultural practices, and the environmental responses of organisms.
nounGravitropism is the growth, bending, or orientation of a plant or other organism in response to gravity. It commonly causes roots to grow downward and shoots to grow upward.
- The growth, bending, or orientation of an organism or organ in response to gravity.
"The roots of the seedling displayed clear gravitropism as they bent toward the soil."
"Researchers used time-lapse photography to document gravitropism in the young roots."
"Disrupting gravitropism can cause a plant to grow with its shoots and roots oriented incorrectly."
The plural is uncommon because gravitropism is usually used as an uncountable name for a biological phenomenon, but it can be used when referring to distinct examples.
"The experiment compared gravitropisms in roots exposed to different gravitational conditions."
Roots bend downward and shoots bend upward: gravity writes the instructions.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does gravitropism come from?
Gravitropism is a modern scientific formation combining gravit-, associated with gravity and Latin gravitas, meaning weight or heaviness, with tropism, from Greek tropos, meaning turn or direction. The term describes a turning or directional growth caused by gravity. Its older synonym geotropism remains in use, but gravitropism has become the standard modern term in biological writing.
Related word forms
How gravitropism is actually used
This is primarily a technical term in plant physiology and related biological fields. It is most often used where the response to gravity is being described specifically, although the older term geotropism remains familiar.
Easily confused with gravitropism
Geotropism is the older term and is still used as a synonym, while gravitropism is the standard modern name for a growth response specifically to gravity.