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title: "Guard cells Under Microscope - Biology Notes Online"
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# Guard cells Under Microscope

Under the microscope, guard cells appear as specialized, kidney-shaped (in dicots) or dumbbell-shaped (in monocots) pairs of cells that flank a central pore called the stoma (plural: stomata) on the surface of leaves, especially on the lower epidermis. Microscopic Appearance of Guard Cells: Guard cells are usually kidney-shaped in dicotyledonous plants (e.g., bean, sunflower) and ... [Read more](https://biologynotesonline.com/microscopic-image/guard-cells-under-microscope/)

Under the microscope, **guard cells** appear as **specialized, kidney-shaped (in dicots)** or **dumbbell-shaped (in monocots)** pairs of cells that flank a central pore called the **stoma (plural: stomata)** on the surface of leaves, especially on the lower epidermis.

**Microscopic Appearance of Guard Cells:**

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Guard cells are usually **kidney-shaped in dicotyledonous plants** (e.g., bean, sunflower) and **dumbbell-shaped in monocotyledonous plants** (e.g., grass, maize).

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They are located in pairs, forming an **elliptical opening (stomatal pore)** between them.

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The **cell wall is unevenly thickened**—the inner wall (towards the stoma) is **thicker and less elastic**, while the outer wall is **thinner and more flexible**, allowing the stoma to open and close with changes in turgor pressure.

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Guard cells have visible **nuclei**, which helps distinguish them from surrounding epidermal cells.

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**Chloroplasts are present in guard cells**, unlike most other epidermal cells, making them appear greener or more granular under higher magnification and proper lighting.

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Under high magnification (typically 400x or more), **cytoplasmic streaming** and the green chloroplasts are often visible within the guard cells.

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The surrounding **epidermal cells are more elongated and irregular**, and they **lack chloroplasts**, which helps highlight the contrast.

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When stained with iodine or safranin, the **cell walls and nuclei** become more prominent for clearer observation.

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In **open stomata**, the stoma appears as a **clear slit or pore** between the two guard cells; in **closed stomata**, the guard cells appear pressed together with little or no visible gap.

**Observation Tips:**

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Best observed using a **peel from the lower epidermis of a leaf** (e.g., from Rhoeo, Tradescantia, or Hibiscus) mounted in water or glycerine.

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Use **bright-field microscopy** at **100x–400x magnification**.

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Apply **safranin or iodine stain** for better contrast if unstained cells are difficult to differentiate.

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Guard cells are **more abundant on the lower epidermis** than on the upper surface.

**Key Identification Features:**

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Kidney or dumbbell shape.

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Present in pairs, forming a pore between them.

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Contain chloroplasts (green coloration under natural light).

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Unequal cell wall thickness.

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Surrounded by non-green epidermal cells.