1. Tropism: The Way Plants Respond to Stimuli
Presentation Created by
Mr. M. Barr, Kleb Intermediate School
With Adaptations by D. Tresten, Schindewolf
Certain materials are included under the fair use exemption of the U.S. Copyright Law and have been prepared according to the multimedia fair use guidelines and are restricted from further use.

2. Stimulus (pl. Stimuli): Cause
Response:
Effect

3. Credit: MSDesign Gallery
Did you know that plants move? Weird, huh?
The idea of plants moving struck David Wyndham as weird, too. After he studied tropism, he wrote a “horror novel” called “Day of the Triffids” about plants that “got even” with humans.
A black and white movie was made of this novel.
The Day of the Triffids By
John Wyndham
Credit: MSDesign Gallery
For more information, go to:

4. Light All plants respond to light Stems and leaves grow toward light
Response to light is phototropism

5. Gravity The response to gravity is called geotropism (or gravitropism)
We do not need to worry about which way to plant a seed because the root grows down and the stem grows up. Why does this happen? It happens because plants respond to the pull of gravity.
Root cells grow toward the pull of gravity; stem and leaf cells grow away from the pull of gravity.
The response to gravity is called geotropism (or gravitropism)

6. Water
A plant’s roots grow toward water (not very strongly; plant must be touching water)
Growth of a plant’s roots toward water is called hydrotropism

7. Touch Some plants respond when they are touched
Grapevines,etc. have tendrils which allow a plant to grow around an object
Response of a plant to touch is thigmotropism

8. Color Plants respond to different colors of light
Response of a plant to color is chromotropism

9. Heat Plants respond to different temperatures
Response of a plant to temperature changes is called thermotropism

10. Examples View the following slides for examples of tropism
(some of which are also called nastic movements)

11. View videos of Geotropism (AKA Gravitropism)
Go to
Click on
Germination
and then
click on
Corn
Or just Click Here

12. See animation and more facts:
View an animation of Thigmotropism (which is sometimes called Nastic Movement)
See animation and more facts:

13. View videos of Thigmotropism (or Nastic Movements)
Go to this site:
and then click on the following words (which can be found on the left side of the page),
or just click on the following :
Sensitive plant
Venus flytrap
Sunflower nutation
Morning glory twining

14. View animation of Phototropism

15. View videos of Phototropism
Go to
Look to the left and click on
Sunflower Dark and Light
and
Dark-Grown Arabidoptris

16. and then click on Cool Corn Phototropism
View a video of corn seedlings growing toward a light close to them and then toward an overhead light (a test of Phototropism)
Go to this site:
and then click on Cool Corn Phototropism

17. REVIEW

18. Name the Types of Tropisms that we Learned
Clue: Water VS No water
Clue: Heat VS Cold
Clue: Close VS Far from Earth
Clue: Touch with a toothpick
Clue: Blue light VS Red light
Clue: Dim light VS Bright light
Hydrotropism
Thigmotropism
Thermotropism
Chromotropism
Phototropism
Geotropism/Gravitropism

19. Word Bank Hydrotropism Thigmotropism Thermotropism Chromotropism
Phototropism
Geotropism/Gravitropism

20. Click when you know the answer:
Tropism
Definition:
Response to light
Response to heat
Response to gravity
Response to moisture
Response to touch
Response to colors
Phototropism
Thermotropism
Gravitropism or Geotropism
Hydrotropism
Thigmotropism
Chromotropism

21. Geotropism/Gravitropism Gravitropism or Geotropism
Try again:
Hydrotropism
Thigmotropism
Thermotropism
Chromotropism
Phototropism
Geotropism/Gravitropism
Tropism
Definition:
Response to touch
Response to water
Response to colors
Response to cold
Response to gravity
Response to too little light
Thigmotropism
Hydrotropism
Chromotropism
Thermotropism
Gravitropism or Geotropism
Phototropism

22. Name the type of Tropism that each of the following investigations is testing…

23. Investigation # What form of tropism is being tested?
Mesh Divider (Inserted to bottom of pan)
Watered
Soil
Dry Soil
Chromotropism
Geotropism
Hydrotropism
Phototropism
Thigmotropism
Seeds =

24. Investigation # What form of tropism is being tested? Chromotropism
Geotropism
Hydrotropism
Phototropism
Thigmotropism
Thermotropism
Plant B
Plant A

25. #
Investigation
What form of tropism do you think the scientist is meaning to test?
What’s wrong with the idea?
Chromotropism
Geotropism
Hydrotropism
Phototropism
Thigmotropism
Thermotropism

26. Investigation # What form of tropism is being tested? Phototropism
Thigmotropism
Thermotropism
Chromotropism
Geotropism
Hydrotropism

27. Investigation # What form of tropism is being tested? Chromotropism
Geotropism
Hydrotropism
Phototropism
Thigmotropism
Thermotropism

28. Investigation # What form of tropism is being tested?
Chromotropism
Geotropism
Hydrotropism
Phototropism
Thigmotropism
Plant in the space shuttle
Same kind of plant in a building on Earth

29. #
Investigation
What form of tropism is being tested? Are there possibly 2 or 3 variables? How could this test be improved?
Chromotropism
Geotropism
Hydrotropism
Phototropism
Thigmotropism
Thermotropism

30. Investigation # What form of tropism is being tested? Chromotropism
Geotropism
Hydrotropism
Phototropism
Thigmotropism
Thermotropism

31. See animation and more facts:#
Investigation
What form of tropism is being tested?
Chromotropism
Geotropism
Hydrotropism
Phototropism
Thigmotropism
Thermotropism
See animation and more facts:

32. Investigation # What form of tropism is being tested?
Are there too many variables in this test?
Chromotropism
Geotropism
Hydrotropism
Phototropism
Thigmotropism
Thermotropism

33. Investigation # What form of tropism is being tested?
Could there be more than one variable affecting the outcome of this test?
Chromotropism
Geotropism
Hydrotropism
Phototropism
Thigmotropism
Thermotropism

34. Oral Review Read the definition Say the answer aloud
Click to see the answer

35. Click when you know the answer:
Tropism
Definition:
Response to light
Response to heat
Response to gravity
Response to moisture
Response to touch
Response to colors
Phototropism
Thermotropism
Gravitropism or Geotropism
Hydrotropism
Thigmotropism
Chromotropism

36. Gravitropism or Geotropism
Try again:
Tropism
Definition:
Response to touch
Response to water
Response to colors
Response to cold
Response to gravity
Response to too little light
Thigmotropism
Hydrotropism
Chromotropism
Thermotropism
Gravitropism or Geotropism
Phototropism

37. Quiz
Number from 1 – 15
Identify the types of tropism

38. This is an example of which form of tropism?#1
This is an example of which form of tropism?
Chromotropism
Geotropism
Hydrotropism
Phototropism
Thigmotropism
Thermotropism

39. #2
Chromotropism
Geotropism
Hydrotropism
Phototropism
Thigmotropism
Thermotropism
Mimosa plants contract when touched. This is an example of what form of tropism?

40. #3
For a Humorous Animation of “Venus Pie Trap,” go to
Venus fly traps close around insects that “irritate” them. This is an example of what form of tropism?
Source & For more information, go to:

41. Investigation #4
What form of tropism is being tested if this bag is taped to a wall?
Chromotropism
Geotropism
Hydrotropism
Phototropism
Thigmotropism
Ziplock baggie, open at top
Paper Towel, moist
1 of 2 seeds 1 is right side up/
other is upside down
(lima beans, peas, corn)
Staples to keep beans from moving

42. Data for Investigation 1: What evidence suggests geotropism?#5
Data for Investigation 1: What evidence suggests geotropism?
Close-up View

43. Investigation #6 What form of tropism is being tested?
Mesh Divider (Inserted to bottom of pan)
Watered
Soil
Dry Soil
Chromotropism
Geotropism
Hydrotropism
Phototropism
Thigmotropism
Seeds =

44. Investigation #7 What form of tropism is being tested? Phototropism
Thigmotropism
Thermotropism
Chromotropism
Geotropism
Hydrotropism
Plant A
Plant B

45. Investigation #8 What form of tropism is being tested? Chromotropism
Geotropism
Hydrotropism
Phototropism
Thigmotropism
Thermotropism

46. Investigation #9 What form of tropism is being tested? Chromotropism
Geotropism
Hydrotropism
Phototropism
Thigmotropism
Thermotropism

47. Investigation #10 What form of tropism is being tested? Chromotropism
Geotropism
Hydrotropism
Phototropism
Thigmotropism
Thermotropism

48. See animation and more facts:
#11
Investigation
What form of tropism is being tested?
Chromotropism
Geotropism
Hydrotropism
Phototropism
Thigmotropism
Thermotropism
See animation and more facts:

49. Investigation #12 What form of tropism is being tested? Chromotropism
Geotropism
Hydrotropism
Thigmotropism
Thermotropism

50. Investigation: #13 What form of tropism is being tested? Chromotropism
Geotropism
Hydrotropism
Phototropism
Thigmotropism
Thermotropism

51. Investigation #14 What form of tropism is being tested?
Chromotropism
Geotropism
Hydrotropism
Phototropism
Thigmotropism
Thermotropism
Plant in the space shuttle
Same kind of plant in a building on Earth

52. Investigation
What form of tropism is being tested? It’s hard to tell, isn’t it? Too many variables!
Plant on the moon
Chromotropism
Geotropism
Phototropism
Thigmotropism
Thermotropism

53. Investigation #15 What form of tropism is being tested? Chromotropism
Geotropism
Hydrotropism
Phototropism
Thigmotropism
Thermotropism

54. Source: http://www.afpmb.org/mpmh/chap2.htm
Forms of Tropism
Know these for the test:
PHOTOTROPISM -- response to light.
GEOTROPISM -- response to earth contact or gravity.
THERMOTROPISM -- response to heat.
HYDROTROPISM -- response to moisture.
CHROMOTROPISM -- response to colors.
THIGMOTROPISM -- response to touch.
Other forms of tropism:
HELIOTROPISM -- response to direct sunlight.
CHEMOTROPISM -- response to chemical stimuli.
ANEMOTROPISM -- response to air current.
Source: