Phototropism
Phototropism is the growth or movement of a plant in the direction of its light source.
Geotropism
Geotropism is a turning or growth movement by a plant or fungus in response to gravity.
Hydrotropism
Hydrotropism is the turning or growth movement by a plant or fungus in response to water.
Thigmotropism
Thigmotropism is the directional growth movement of a plant part in response to the touch of
an object. For example a climbing vine wraps around a stem or a Venus Fly Trap closes on a fly.
Chemotropism
Chemotropism is the directional growth movement of a plant part in response to chemicals.
For example, the growth of pollen tubes towards ovules during the process of fertilization.
a) Which picture shown in this figure is the most likely outcome? Why?
b) What structure shown in this image produces sugars?
c) What structure absorbs water and nutrients and stores food?
d) What structure is responsible for transferring materials and supporting the plant?
e) Which structure shown in this image demonstrates negative geotropism?
f) Which structure in this image demonstrates positive geotropism?
A
g) What type of tropism is plant A demonstrating?
h) What type of tropism is plant B demonstrating?
B
i) What stimulus do you think made these roots
grow in one direction?
j) What is this type of tropism called?
k) This potato started growing after being left too
long on the counter. There are two types of
tropisms occurring at the same time here. Can
you identify them? Please explain.