.  what is an example of a nastic movement?
Best Answer: Nastic Movement: Nastic movements are non-directional responses to stimuli (e.g. temperature, humidity, light irradiance). The movement can be due to changes in turgor or changes in growth. Nastic movements differ from tropic movements in that the direction of tropic responses depends on the direction of the stimulus, whereas the direction of nastic movements is independent of the stimulus. Viruses and other pathogens also affect what is called host tropism or cell tropism in which case tropism refers to the way in which different viruses/pathogens have evolved to preferentially target specific host species, or specific cell types within those species. The “motor” that drives most nastic movements is a controlled change in turgor pressure, which is the pressure exerted on a cell wall due to movement of water into the cell. (Photograph courtesy C.G.N. Turnbull). Nastic responses differ from tropisms because the direction of movement is not related to the stimulus direction but is instead dictated by the plant. The rate or frequency of these responses increases as intensity of the stimulus increases. An example of such a response is the opening and closing of flowers (photonastic response). Nastic responses are usually associated with plants.. Tropism Movement: A tropism (from Greek, tropos, to turn) is a biological phenomenon, indicating growth or turning movement of a biological organism, usually a plant, in response to an environmental stimulus. Nastic movements are plant movements that occur in response to environmental stimuli but unlike tropic movements, the direction of the response is not dependent on the direction of the stimulus. Some of the most spectacular plant movements are nastic movements. These include the closing of the carnivorous Venus Flytrap leaf when it captures prey or the folding of the mimosa leaf when it is disturbed. Home. Movie Categories. 1  Germination. 2  Photomorphogenesis. 3  Tropisms. 4  Nastic Movements. 5  Venus flytrap. 6  Sensitive plant. The most widely occurring nastic movements are probably day-and-night movements, known as nyctinastic movements. Another important kind is thigmonastic movements, triggered by touch or other mechanical stimuli. In addition, the orientational changes that occur in nastic movements are temporary; they are reversible and repeatable. The tropisms, in contrast, are generally irreversible. Nastic movements are common in certain plant families, especially among the legumes (family Fabaceae, formerly Leguminosae). Plants, unlike animals, are sedentary organisms, but they are capable of some limited movements. These include nastic movements, which enable plants to adapt rapidly to changes in their environment by changing orientation. Nastic movements and tropisms, or growth movements, are two important, but different, kinds of movements in plants. In nastic movements, the direction of movement is determined by the anatomy of the plant rather than by the position of the origin of the stimulus.
Examples : temperature, humidity, light irradiance.