Tropism
By Gavin Molina
Phototropism
The orientation of a plant or other organism in response to light, either toward the source of light ( positive phototropism ) or away from it ( negative phototropism ).
Hyrdrotropism
The growth or turning of plant roots toward or away from moisture.
Thigmotropism
The turning or bending of a plant or other organism in response to a touch stimulus.
Gravitropism
Gravitropism (also known as geotropism) is a coordinated process of differential growth by a plant or fungus in response to gravity pulling on it. It is a general feature of all higher and many lower plants as well as other organisms.
Auxin
A plant hormone which causes the elongation of cells in shoots and is involved in regulating plant growth.