(Of the periodic movement of flowers or leaves) caused by nightly changes in light intensity or temperature.
- 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.
- 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.
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