• WordNet 3.6
    • n phototropism an orienting response to light
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Webster's Revised Unabridged Dictionary
    • Phototropism (Microbiology) exhibiting movement in a direction toward (positive phototropism) or away from (negative phototropism) a source of light.
    • Phototropism (Plant Physiol) The tendency of growing plant organs to move or curve under the influence of light. In ordinary use the term is practically synonymous with heliotropism.
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Century Dictionary and Cyclopedia
    • n phototropism The growth or the bending of organisms or of parts of organisms in relation to light; heliotropism.
    • n phototropism Same as phototaxis, 2.
    • n phototropism Same as phototropy, 2.
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Webster's Revised Unabridged Dictionary
Photo-, + Gr. to turn


In literature:

I shall now describe the phototropic effect of unilateral light in pulvinated, and in growing organs.
"Life Movements in Plants, Volume II, 1919" by Sir Jagadis Chunder Bose

In news:

Single Page ( iStock Photo/phototropic ).