phototropism

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phototropism

 [fo-tot´ro-pizm]
1. tropism of an organism in response to light; it may be either positive (toward the light) or negative (away from the light).
2. change of color produced in a substance by the action of light. adj., adj phototrop´ic.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

pho·tot·ro·pism

(fō-tot'rō-pizm),
Movement of a part of an organism toward (positive phototropism) or away from (negative phototropism) the stimulus of light. Compare: phototaxis.
[photo- + G. tropē, a turning]
Farlex Partner Medical Dictionary © Farlex 2012

phototropism

(fō-tŏt′rə-pĭz′əm, fō′tō-trō′-)
n.
Growth or movement of a sessile organism toward or away from a source of light.

pho′to·tro′pic (fō′tə-trō′pĭk) adj.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

pho·tot·ro·pism

(fō-tot'rŏ-pizm)
Movement of a part of an organism toward (positive phototropism) or away from (negative phototropism) the stimulus of light.
Compare: phototaxis
[photo- + G. tropē, a turning]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

phototropism

a bending growth movement of parts of a plant in response to a light stimulus. The movement produced by unequal growth is due to differences in AUXIN concentration. For example, most seedlings are positively phototropic, growing towards a light stimulus, because there is a greater concentration of auxin on the side furthest away from the light, giving greater growth on this side. Roots, on the other hand, are often negatively phototropic, growing away from a light source.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005

phototropism 

Reaction of certain plants and animals to move towards (positive phototropism) or away from (negative phototropism) a source of light.
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann