D defs.my
Entry 2 senses Webster, 1913

Phototonus

· Pho·tot·o·nus · IPA
01 n. A motile condition in plants resulting from exposure to light.
  1. 1.
    A motile condition in plants resulting from exposure to light.(Bot.)
  2. 2.
    An irritable condition of protoplasm, resulting in movement, due to a certain intensity of light.(Physiol.)