heliotropism

[ hee-lee-o-truh-piz-uhm, hee-lee-uh-troh-piz-uhm ]

Phonetic (Standard)IPA

noun

heliotropism

/ ˌhiːlɪˈɒtrəˌpɪzəm; ˌhiːlɪəʊˈtrɒpɪk /

the growth of plants or plant parts (esp flowers) in response to the stimulus of sunlight, so that they turn to face the sun

heliotropism

/ hē′lē-ŏt′rə-pĭz′əm /

The growth or movement of a fixed organism, especially a plant, toward or away from sunlight. Heliotropism can be easily seen in sunflowers, which slowly turn their large flowers so that they continually face the sun.

First recorded in 1850–55; helio- + -tropism

If it acts in a one-sided way, it causes the particular form of stimulation which we call phototaxis or heliotropism.

This 'midday sleep' has been termed para-heliotropism by Darwin.

We notice also the reverse phenomenon, namely, that chemical changes produced in the animal destroy its heliotropism.

These periodic motions are determined to a large extent, if not exclusively, by the heliotropism of these animals.

This problem reduces itself simply to that of the method whereby the gametes transmit heliotropism to the larvae or to the adult.

April 19, 2024tortuous

[tawr-choo-uhs ]

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