2. Tropisms
Tropisms - a biological phenomenon, indicating
growth or turning movement of a biological
organism, usually a plant, in response to an
environmental stimulus.
The word tropism comes from the Greek trope ("to
turn" or "to change"). Tropisms are usually
named for the stimulus involved and may be
either positive (towards the stimulus) or negative
(away from the stimulus).
3. 1. Phototropism is the growth response of a
plant in response to light direction.
4. 2. Geotropism is the growth response of a plant in
response to gravity.
5. 3. Thigmotropism is the growth response of a plant
to physical contact (touch).