phototropism: meaning, definition, pronunciation and examples

Rare/Very Low
UK/ˌfəʊtəʊˈtrəʊpɪz(ə)m/US/ˌfoʊtoʊˈtroʊpɪzəm/

Academic, Technical/Scientific

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Quick answer

What does “phototropism” mean?

the growth or movement of an organism (especially a plant) in response to light.

Audio

Pronunciation

Definition

Meaning and Definition

the growth or movement of an organism (especially a plant) in response to light.

In biology, the directional response or orientation of a plant or other sessile organism relative to the direction of light, typically enabling optimal light absorption for photosynthesis.

Dialectal Variation

British vs American Usage

Differences

There are no significant differences in meaning or usage between UK and US English for this highly technical term.

Connotations

Neutral, purely descriptive scientific term in both variants.

Frequency

Identically rare and confined to specialised discourse in both regions.

Grammar

How to Use “phototropism” in a Sentence

[Organism] exhibits phototropism.The phototropism of [plant part] is caused by...Positive phototropism in response to [light source].

Vocabulary

Collocations

strong
positive phototropismnegative phototropismexhibit phototropismplant phototropismstem phototropism
medium
demonstrate phototropismshow phototropisma classic example of phototropismdirectional phototropism
weak
rapid phototropismblue-light phototropismstudy phototropismmechanism of phototropism

Examples

Examples of “phototropism” in a Sentence

verb

British English

  • No verb form in common use. The related verb is 'to phototropise' but it is extremely rare.

American English

  • No verb form in common use. The related verb is 'to phototropize' but it is extremely rare.

adverb

British English

  • The stem grew phototropically towards the window.
  • No common adverbial use.

American English

  • The shoots bent phototropically after exposure.
  • No common adverbial use.

adjective

British English

  • The seedling's phototropic curvature was measured.
  • They studied the phototropic mechanism in oat coleoptiles.

American English

  • The plant's phototropic response was rapid.
  • Research focuses on phototropic signaling pathways.

Usage

Meaning in Context

Business

Not used.

Academic

Used in biology, botany, plant physiology, and environmental science textbooks and papers.

Everyday

Virtually never used in everyday conversation.

Technical

The primary domain of use; precise term in botanical and biological research.

Vocabulary

Synonyms of “phototropism”

Strong

light-oriented growthphototropic response

Neutral

heliotropism (when specifically towards sunlight)

Weak

light-seekingsun-following (colloquial/descriptive)

Vocabulary

Antonyms of “phototropism”

skototropism (growth towards darkness, in some plants)apheliotropism (growth away from the sun)

Watch out

Common Mistakes When Using “phototropism”

  • Incorrect spelling: *phototropicism, *phototropinism.
  • Mispronunciation: stressing the first syllable (*FOE-toe-tropism) instead of the third (photo-TROPE-ism).
  • Using it to describe animal behaviour (e.g., moths to a flame), which is phototaxis, not phototropism.

FAQ

Frequently Asked Questions

No. Photosynthesis is the process of converting light energy into chemical energy (food). Phototropism is the directional growth movement in response to light, which helps plants position themselves to optimise photosynthesis.

Most above-ground plant parts (like stems and leaves) show positive phototropism to maximise light capture. Some roots and certain specialised plants (like some vines) may show negative phototropism (skototropism) to grow towards dark, shaded areas for support.

No. The directed movement of motile organisms (like insects) towards or away from light is called phototaxis. 'Tropism' is specifically for the growth responses of non-motile organisms like plants and fungi.

Heliotropism is a specific type of phototropism where the plant tracks the movement of the sun across the sky during the day (e.g., sunflowers). Phototropism is the broader term for any light-directed growth.

the growth or movement of an organism (especially a plant) in response to light.

Phototropism is usually academic, technical/scientific in register.

Phototropism: in British English it is pronounced /ˌfəʊtəʊˈtrəʊpɪz(ə)m/, and in American English it is pronounced /ˌfoʊtoʊˈtroʊpɪzəm/. Tap the audio buttons above to hear it.

Phrases

Idioms & Phrases

  • No common idioms use this term.

Learning

Memory Aids

Mnemonic

PHOTO (light) + TROPISM (turning) = turning towards light. Think of a sunflower performing a PHOTO shoot as it TROTS to follow the sun.

Conceptual Metaphor

PLANTS ARE LIGHT-SEEKERS; LIGHT IS A GUIDE/DIRECTIONAL SIGNAL.

Practice

Quiz

Fill in the gap
The bending of a plant stem towards a light source is a classic example of .
Multiple Choice

What does 'negative phototropism' refer to?