tropo” – ”turn”)worleyscience.weebly.com/uploads/5/5/5/0/5550484/new_tropism.pdf · TROPISM...
Transcript of tropo” – ”turn”)worleyscience.weebly.com/uploads/5/5/5/0/5550484/new_tropism.pdf · TROPISM...
TROPISM Plant growth in response to a stimulus (Something that causes a response; water light, gravity, touch)
What is
tropism?
There are many types of tropisms :
• Phototropism
• Geotropism
•Thigmotropism
• Hydrotropism
• Chemotropism
• Thermotropism
(“tropo” – ”turn”)
What is
gravitropism?
(“Geo” – Earth)
the growth of a plant in response to gravity.
Positive Geotropism growth of a plant towards the center of the earth with gravity. (roots growing down)
Negative Geotropism growth of a plant away from the center of the earth-opposing gravity (stems grow up)
Negative Geotropism
Positive Geotropism
Why is
gravitropism so
important?
•Pulls roots down to anchor a plant • Roots can get needed water and minerals if they stay in the soil
What is
phototropism? (“Photo” – light)
The growth response of a plant in response to light direction
Ex. Stems growing
toward the window
to get to the light
Why is
phototropism
so important?
Enables leaves to be in the best position possible to receive adequate light for photosynthesis
What is
thigmotropism?
(“Thigmo” – touch)
the growth of a plant in response to touch/contact.
Vines growing on a wall or fence
Tendrils on a sweet pea