To Observe Stomata on Leaf Surface (Class 10 Biology Practical)
To prepare temporary mounts of leaf epidermal cells and observe stomata, identifying guard cells and subsidiary cells.
TL;DR: To prepare temporary mounts of leaf epidermal cells and observe stomata, identifying guard cells and subsidiary cells.
Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated
Aim: To prepare temporary mounts of leaf epidermal cells and observe stomata, identifying guard cells and subsidiary cells.
Materials Required
- Fresh leaf (mint or hibiscus)
- Microscope slides
- Cover slips
- Distilled water
- Safranin dye
- Compound microscope
- Forceps
- Scalpel
Theory
Stomata are pores in the leaf epidermis surrounded by a pair of guard cells that control gas exchange and transpiration. Guard cells change shape to open or close the stomatal pore. Subsidiary cells surround the guard cells. Dicot leaves typically have more stomata on the lower surface (abaxial) than upper surface (adaxial).
Procedure
- Pick a fresh leaf from a plant like mint or hibiscus
- Place the leaf on a microscope slide with the lower surface facing up
- Use a scalpel to scrape the lower surface of the leaf gently
- Remove the scraped surface with forceps to expose the epidermal layer
- Add a drop of distilled water and prepare a wet mount with cover slip
- Stain with safranin dye by drawing it through the mount
- Observe under high magnification (40X objective)
- Identify guard cells (bean-shaped), subsidiary cells, and the pore (stoma)
Observation
The lower surface of the leaf shows numerous bean-shaped guard cells arranged in pairs with a pore (stoma) between them. Subsidiary cells are visible surrounding the guard cells. The upper surface has fewer or no stomata in typical dicot leaves.
Result
Stomata are clearly observed on the leaf epidermis, with guard cells surrounding each pore. The guard cells contain chloroplasts and control the opening and closing of stomata for gas exchange.
Precautions
- Scrape gently to avoid damaging the underlying tissues
- Use fresh leaves for better observation
- Focus carefully to see the epidermal layer clearly
- Compare upper and lower surfaces to note the difference in stomatal density
- Observe multiple stomata to confirm the structure
Viva Questions
What are stomata?
Stomata are tiny pores on the leaf surface through which gas exchange and transpiration occur.
What are guard cells?
Guard cells are a pair of specialized cells that surround each stoma and control its opening and closing.
Why do dicot leaves have more stomata on the lower surface?
The lower surface is protected from direct sunlight, reducing water loss. This surface orientation helps control transpiration.
What do guard cells contain?
Guard cells contain chloroplasts that help them change shape in response to water uptake or loss.
More Class 10 Biology Practicals
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- To Study Osmosis Using a Potato Osmometer
- To Observe Onion Peel Cells Under a Microscope
- To Prepare a Temporary Mount of a Leaf
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- To Identify Different Parts of an Embryo of a Dicot Seed
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