1. Tropisms and Photosynthesis

2. Tropisms
Tropism is the growth of a plant towards or away from a stimulus
A Stimulus is something that causes change like light, gravity, water, or contact.
There are positive and negative tropisms:
Positive Tropisms are towards the stimulus
Negative Tropisms are away from the stimulus

3. Phototropism/Gravitropism

4. Types of Tropisms Phototropism ‘Photo-’ means ‘light’
Phototropism is the bending of a plant towards light (remember that ‘towards’ is a positive tropism)
This is caused by a plant hormone called Auxin
Auxin promotes plant growth and cell elongation.

5. Types of Tropisms Gravitropism AKA Geotropism
‘Gravi-’ refers to ‘Gravity’
Gravitropism is the bending of a plant towards or away from gravity
-Roots are a positive gravitropism and grow towards gravity
-Shoots are a negative gravitropism and grow away from gravity

6. Thigmotropism

7. Types of Tropisms Thigmotropism ‘Thigmo-’ refers to ‘Touch’
Thigmotropism is the bending of a plant in response to touch
You see this with vines that twist around trees or buildings
This is what venus fly traps are able to do

8. Venus Fly Traps

9. Types of Tropisms Hydrotropism Hydro – means “water”
Hydrotropism is the bending of a plant towards water.
This is what happens with tree roots when they get into the pipes in your house.

10. Photosynthesis
Plants utilize tropisms to increase the amount of sunlight that they can acquire to maximize photosynthesis
See if you can write the chemical equation for photosynthesis in your notebook.
Reactants → Products

11. Photosynthesis
Now I will give you the components, see if you can get them on the correct side of the equation: C6H12O6 Energy H2O O2 CO2 ? ?

12. Photosynthesis
Here is the equation with everything on the correct side. Check your work, but remember that it doesn’t matter which order you have them in so long as they are on the correct side. __CO2 + __H2O + Energy  __C6H12O6 + __O2 Now Balance the Equation

13. Photosynthesis
Your final equation should look like this: Now write the equation for Respiration!

14. Name that Tropism! What type of tropism is this? Positive or Negative?
Gravitropism

15. Name that Tropism! What type of tropism is this? Positive or Negative?
Thigmotropism

16. Name that Tropism! What type of tropism is this? Positive or Negative?
Gravitropism

17. Name that Tropism! What type of tropism is this? Positive or Negative?
Phototropism

18. Positive Hydrotropism
Name that Tropism!
What type of tropism is this? Positive or Negative?
Positive Hydrotropism

19. Name that Tropism! What type of tropism is this? Positive or Negative?
Thigmotropism

20. Name that Tropism! What type of tropism is this? Positive or Negative?
Phototropism