• (a.) Manifesting heliotropism; turning toward the sun.
the movement of plant parts in response to a light source
Any device (or plant) that follows the sun's apparent movement across the sky. Related category • SOLAR ENERGY AND POWER
the movement of plant parts in response to a light source
Turning toward the sun.
He`li·o·trop'ic adjective (Botany) Manifesting heliotropism; turning toward the sun. 
Heliotropic is a biological term for plants which turn their stems so as to expose as much leaf surface to the sunlight as possible.
heliotropic 1. Oriented toward sunlight or other light. 2. Describing a plant that grows, or moves, toward the sun. 3. The description of a deice that follows the sun's apparent movement across the sky.
Any device (or plant) that follows the sun's apparent movement across the sky.