1. Plants Move

2. TROPISM
is a biological phenomenon, indicating growth or turning movement a plant in response to an environmental stimulus

3. TROPISM POSITIVE NEGATIVE If the plant moves TOWARD the stimulus
If the plant moves AWAY from the stimulus

4. Phototropism
Movement of plants toward light Why? Maximize amount of sun for photosynthesis to make their food. Phototropism

5. Gravitropism Movement of plants in response to gravity
Positive is toward gravity (roots grow down)
Negative is away from gravity (shoot, stems, and leaves grow up)
Why?
Allows plants to grow properly and get nutrients and sunlight

6. Hydrotropism Movement by plants toward water. Why?
Roots search for and grow toward water, because it is needed for photosynthesis and to support cell structure.

8. Thigmotropism Plants moving in response to touch.
Positive is toward touch (vines wrap around structures)
Negative is away from touch (some plants close up when touched)
Why?
to support leaves as they grow higher to reach the sun to make more food (photosynthesis).

9. Gravitropism Gravity causes a response in plant growth
In the picture above, which part of the plant exhibits positive tropism, and which exhibits negative tropism?

10. Hydrotropism The way a plant grows or bends in response to water
Why would it be important for some parts of a plant to be pulled toward water?

11. Thigmotropism Plants bend and grow because of touch.
What are some other ways a plant can be “touched”?

12. Phototropism The way a plant grows or bends in response to light.
Why do you think sunflowers were given their nickname?

13. Hydroptropism

14. Gravitropism

15. Phototropism

16. Gravitropism

17. Phototropism

18. Thigmotropism

19. TROPISM QUIZ
Identify the type of tropism in the following pictures

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