Definition of phototaxis in English:

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Pronunciation: /ˌfəʊtəʊˈtaksɪs/

noun (plural phototaxes)

[mass noun] Biology
The bodily movement of a motile organism in response to light, either towards the source of light ( positive phototaxis) or away from it ( negative phototaxis). Compare with phototropism.
Example sentences
  • Wild-type flies showing normal phototaxis consistently moved towards the light to end up in the last tube by the end of the trial.
  • Namely, two rhodopsins that absorb in different spectral bands and optimally function at different intensity ranges generate two photoreceptor currents that control flagella movement during phototaxis.
  • Far-red or red background lights irradiated vertically from above drastically inhibited phototaxis toward red light or far-red light, respectively.



Example sentences
  • From a screen of 18,500 mutagenized flies, 171 phototactic mutants were recovered of which 15 appear to be specifically defective in synaptic transmission on the basis of the results of electroretinogram recordings.
  • Lebert and Hader observed a curious phototactic phenomenon in eyeless mutants of Euglena, i.e. it swam perpendicularly with respect to the incident light, namely, diaphototaxis.
  • Most unicellular flagellate algae are phototactic, i.e., capable of orientation with respect to the direction of light.
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