Dictionary > Nyctinasty


noun, plural: nyctinasties
(botany) The nastic movement of plant parts such as leaves and petals in response to darkness
Nyctinasty refers to the nastic movement of leaves or petals of higher plants in response to darkness (or the alternation of day and night). The closing of a flower at dusk, for instance, is a biological rhythmic event. Another is the sleep movement of the legume leaves during the night.
Nyctinasty is diferent from a tropic movement (tropism). Tropism is a directional movement or growth response of a cell or an organism to a stimulus, which may either be positive or negative depending on the source and kind of stimulation. In other words, tropism is associated with the growth response of the plant to a stimulus. Phototropism, for instance, is a form of tropism wherein plants grow towards the source of light (positive tropism). In nyctinasty, some plants are able to assume a position at night that is different from their position during daytime. It is a biological rhythm since this behavior recurs in each circadian day. The sleeping position of these plants are said to be associated with pulvinar movement, circadian clock, and light signal transduction through phytochrome. Pulvinar movement involves pulvinar cells at the base of a plant leaf (or leaflet) or at the apex of the petiole that facilitates nyctinastic and nastic movements in a mechanism similar to stomatal closure.

  • nyctinastism
  • nyctitropism

See also:

  • nastic movement
  • biological rhythm
  • Related form(s):

    • nyctinastic (adjective)

    You will also like...

    The process of photosynthesis
    Photosynthesis – Photolysis and Carbon Fixation

    Photosynthesis is the process that plants undertake to create organic materials from carbon dioxide and water, with the ..

    Hormone Production
    Hormone Production

    Hormones are chemical messengers produced by specialized glands and they were produced by switching on the genes designe..

    DNA carries genes coding for proteins
    Genetic Information and Protein Synthesis

    Genes are expressed through the process of protein synthesis. This elaborate tutorial provides an in-depth review of the..

    Homeostatic Mechanisms and Cellular Communication
    Homeostatic Mechanisms and Cellular Communication

    Homeostasis is the relatively stable conditions of the internal environment that result from compensatory regulatory res..

    Primitive Animals

    Life, as we know it today, is presumed to have started in the sea and many of them were likely eukaryotic animal-like or..

    green leaf - close up view

    Leaves are the major photosynthetic organ of a plant. Apart from that, they are also crucial to water movement. In this ..