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nyctinastic Syllabification: nyc·ti·nas·tic
Pronunciation: /ˌniktəˈnastik/

Definition of nyctinastic in English:


(Of the periodic movement of flowers or leaves) caused by nightly changes in light intensity or temperature.
Example sentences
  • Leaflets of nyctinastic plants assume a vertical (i.e. closed) position in darkness and revert to horizontal orientation upon illumination.
  • Leaf-movement in nyctinastic plants has long been believed to be controlled by plant hormones that are common among all nyctinastic plants.
  • Several systems of measurement have been used to characterize leaf or leaflet orientation during nyctinastic and heliotropic movement.


Pronunciation: /ˈniktəˌnastē/
Example sentences
  • The trifoliate leaflets are closed as in nyctinasty.
  • We found that nyctinasty is controlled by a periodic change of the internal concentration of leaf-opening and leaf-closing substances in the plant body.
  • What is the selective advantage to plants of nyctinasty (sleep movements) which closes flowers in the evening?


Early 20th century: from Greek nux, nukt- 'night' + nastos 'pressed' + -ic.

Definition of nyctinastic in:
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