[nas-tik] 
| of or showing sufficiently greater cellular force or growth on one side of an axis to change the form or position of the axis. |
| a combining form occurring in adjectives corresponding to nouns ending in -nasty: hyponastic. |
| nas·tic (nās'tĭk) adj. Of, relating to, or characterized by the tendency in plant parts to move in a direction determined by an internal stimulus, as an increased rate of cellular growth on one surface or side of the plant part. [Greek nastos, pressed close (from nassein, to press) + -ic.] |