TROPISM
NEXT
TROPISM refers to
plant growth in response to
something in its surroundings.
.
There are three main types of
tropisms :
• Phototropism
• Geotropism
•Hydrotropism
NEXT
GEOTROPISM
* Geo means earth.
Geotropism is the growth
of a plant in response to
gravity.
Negative Geotropism
Positive Geotropism
Plant grows down with gravity.
Ex. roots growing down
Negative Geotropism
is the growth of a plant opposite
to the pull of gravity
Ex. stems grow up
Positive Geotropism
NEXT
IMPORTANCE OF
GEOTROPISM
• Pulls roots down to anchor a plant
• Roots can get needed water and
minerals if they stay in the soil
NEXT
PHOTOTROPISM
(“Photo” – light)
Plant growth toward a source of light is
PHOTOTROPISM.
Ex. Stems growing toward the window to get
to the light
NEXT
IMPORTANCE OF
PHOTOTROPISM
Lets leaves be in the best position
possible to receive enough light for
photosynthesis
http://www.darienps.org/teachers/otterspoor/botany/tropism
s/Gravitropismwlight.jpg
NEXT
Hydrotropism
Hydro means water.
Hydrotropism refers to a
plant growing toward a
source of water.
This allows the plant to stay alive and to do
photosynthesis.