Control and Coordination | Activities in Text Book with Solution
Activity 7.2
Fill a conical flask with water.
Cover the neck of the flask with a wire mesh.
Keep two or three freshly germinated bean seeds on the wire mesh.
Take a cardboard box which is open from one side.
Keep the flask in the box in such a manner that the open side of the box faces light coming
from a window (Fig. 7.5).
from a window (Fig. 7.5).
After two or three days, you will notice that the shoots bend towards light and roots away from light.
Now turn the flask so that the shoots are away from light and the roots towards light. Leave it undisturbed in this condition for a few days.
Have the old parts of the shoot and root changed direction?
- ✅ Answer: The old parts of the shoot and root have no noticeable change in direction.
Are there differences in the direction of the new growth?
- ✅ Answer: New growth parts show change in direction. i.e., shoot bends towards light and roots bend away from it.
What can we conclude from this activity?
- ✅ Answer: Shoots show phototropism and the roots show geotropism.
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| Fig. 7.5 |