Phototonus

1 definition found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Phototonus \Pho*tot"o*nus\, n. [NL. See {Photo-}, and {Tone}.]
     1. (Bot.) A motile condition in plants resulting from
        exposure to light. -- {Pho`to*ton"ic}, a.
        [1913 Webster]
  
     2. (Physiol.) An irritable condition of protoplasm, resulting


        in movement, due to a certain intensity of light. --
        {Pho`to*ton"ic}, a.
        [Webster 1913 Suppl.]