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Nastic movements are non-directional responses to stimuli (e.g. temperature, humidity, light irradiance), and are usually associated with plants. The movement can be due to changes in turgor or changes in growth (therefore K+ ion concentration usually controls such movement is plants). 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's position. 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). They are named with the suffix "-nasty" and have prefixes that depend on the stimuli: * Epinasty: downward-bending from growth at the top, for example, the bending down of a heavy flower.〔(epinasty - Dictionary of botany )〕 * Hyponasty * Photonasty: response to light * Nyctinasty: movements at night or in the dark * Chemonasty: response to chemicals or nutrients * Hydronasty: response to water * Thermonasty: response to temperature * Geonasty/gravinasty: response to gravity * Thigmonasty/seismonasty/haptonasty: response to contact The suffix may come from Greek νάσσω = "I press", ναστός = "pressed", ἐπιναστια = "the condition of being pressed upon". ==See also== For other types of movement, see: * Taxis * Kinesis * Tropism 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Nastic movements」の詳細全文を読む スポンサード リンク
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