phototropically

Phototropically means in response to light, particularly through growth or movement directed by a light stimulus. The word is most often encountered in discussions of plants and is especially familiar in descriptions of seedlings bending toward a window or growing toward a brighter area. Uneven growth causes this directional movement: cells on the shaded side of a stem or shoot elongate more than those on the illuminated side. Phototropically does not inherently mean toward light, because the direction must be made clear from context; positive and negative phototropic responses are distinguished according to whether the organism moves toward or away from the stimulus. Although a fairly specialized adverb, it succinctly describes a conspicuous biological behavior and is especially useful in gardening, botany, and discussions of plant responses to their environment.

In a manner determined by growth or movement in response to light. It is most often used to describe plants that bend or grow toward a light source.

Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.

Where does phototropically come from?

Phototropically is an adverb formed from phototropic, which in turn combines elements from Greek phōtos, meaning “light,” and tropē, meaning “turn” or “direction.” The same elements appear in phototropism and tropism, terms for directional growth or movement in response to an external stimulus. The related heliotropic derives from Greek hēlios, meaning “sun,” and refers more specifically to orientation toward the sun.

Related word forms

How phototropically is actually used

This is chiefly a technical botanical term. It describes the manner of a phototropic response but does not by itself specify whether the response is toward light or away from it.

Easily confused with phototropically

Rhymes with phototropically