Pho*tot"o*nus (?), n. (Physiol.) An irritable condition of protoplasm, resulting in movement, due to a certain intensity of light. -- Pho`to*ton"ic (#), a.

Pho*tot"o*nus (?), n. [NL. See Photo- , and Tone.] (Bot.) A motile condition in plants resulting from exposure to light. -- Pho`to*ton"ic (#), a.

Pho*tot"o*nus (?), n. (Physiol.) An irritable condition of protoplasm, resulting in movement, due to a certain intensity of light. -- Pho`to*ton"ic (#), a.