Very little attention has been given to the subject of heliotropism until within a few recent years.
We have mentioned the newly hatched larv of the barnacle in connection with heliotropism.
We notice also the reverse phenomenon, namely, that chemical changes produced in the animal destroy its heliotropism.
If it acts in a one-sided way, it causes the particular form of stimulation which we call phototaxis or heliotropism.
The heliotropism of animals is identical with the heliotropism of plants.
These periodic motions are determined to a large extent, if not exclusively, by the heliotropism of these animals.
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.
heliotropic adjective (hēl'lē-ə-trō'pĭk, -trŏp'ĭk)