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๐ฌ Think about it
A leaf takes in carbon dioxide and gives out oxygen. But it has no nose or mouth. So how do gases get in and out? The answer is hidden in tiny doors too small to see. Let us look closely.
How do leaves take in and give out gases?
- Photosynthesis needs carbon dioxide and gives out oxygen.
- Leaves have tiny pores on their surface called stomata.
- Stomata help in the exchange of gases.
- We can see them under a microscope on a leaf peel.
Example:
A peel from a rhoeo leaf seen under a microscope shows many tiny pores, which are stomata.
In this Activity, we will look at a leaf peel under a microscope to find the tiny pores called stomata.
Materials needed
A leaf (rhoeo, money plant, onion, hibiscus, coleus, or grass), a beaker, watch glass, microscope slide, forceps, ink, dropper, coverslip, and a microscope.
Procedure
1. Put a leaf in a beaker filled with water.
2. Carefully peel a thin layer from the lower surface of the leaf.
3. Place the peel in a watch glass with water.
4. Put a drop of water on a slide and transfer the peel onto it with forceps.
5. Put a drop of ink on the peel with a dropper.
6. Cover with a coverslip and observe under a microscope.
2. Carefully peel a thin layer from the lower surface of the leaf.
3. Place the peel in a watch glass with water.
4. Put a drop of water on a slide and transfer the peel onto it with forceps.
5. Put a drop of ink on the peel with a dropper.
6. Cover with a coverslip and observe under a microscope.
Observation
Tiny pores are seen scattered on the leaf peel.
Explanation
These tiny pores are called stomata. They are present on the leaf surface and help in the exchange of gases.
โ Summary
- Thin peel on slide
- Viewed under microscope
- Tiny pores seen
- These pores are stomata
Important Points
- Stomata are tiny pores on the leaf surface.
- They help exchange carbon dioxide and oxygen.
โ Test Yourself
-
What are stomata?
View Answer
Tiny pores on the surface of leaves. -
What do stomata help with?
View Answer
The exchange of gases. -
From which surface do we take the peel?
View Answer
The lower surface of the leaf. -
How can we see stomata?
View Answer
Under a microscope, on a thin leaf peel. -
Name one plant whose leaf can be used.
View Answer
Rhoeo (also money plant, onion, hibiscus, coleus, or grass).
Important Definitions
- Stomata — tiny pores on the surface of leaves that help in the exchange of gases.
