Tropism

When we're not feeling well, there's a tropism toward sweet things.

Source: tatoeba (13103436)

Orientation and tropism are synonymous expressions; that gatherings [of Paramecium] take place is a consequence of the orientation, and therefore throws no light whatever upon the tropisms. (Gatherings, however, are not always indicative of a tropism, i.e., of an orientation, but may be due to kinesis […]

Source: wiktionary

Phototropic orientation of an embryo plant in zero gravity […] On earth, a germinated seedling can be placed in any position and the radicle will invariably turn the embryo plant "downward" and the hypocotle "upward". This is because positive root tropism toward gravity and negative stem tropism away from gravity. In the absence of gravity, will the plumules and the stem of the embryo plant reacting positively to phototropism guide the entire plant including the root system for its directional orientation?

Source: wiktionary

Tropism means that the roots or branches move by turning towards or turning away from environmental stimuli. We have implemented this behavior in the roots of the plantoid [i.e., a robot or synthetic organism designed to act like a plant], integrating sensors and using an adaptive material for growing.

Source: wiktionary