Cotton Leaf Cross Section Under the Microscope
Cotton Leaf (Cross Section), Gossypium hirsutum
This is a cross section of a cotton leaf stained with safranin and fast green. It shows the classic layers of a dicot leaf, from the upper skin through the food-making cells to the vein in the middle.
This is a cross section of a cotton leaf (Gossypium hirsutum), stained with Safranin and Fast Green, with a single layer of epidermis covering the top and bottom surfaces. Just under the top surface is the palisade layer, tall cells packed side by side where most photosynthesis happens. Below it, the spongy layer has loose cells with air spaces that let gases move through the leaf. The thick midrib holds the main vein, with xylem to carry water and phloem to carry sugar. Students can compare the tightly packed palisade cells with the loose spongy cells.
Labeled cotton leaf cross section under the microscope
- Upper epidermis: Single layer of cells on the upper surface
- Palisade mesophyll: Tall, tightly packed cells where most photosynthesis happens
- Spongy mesophyll: Loose cells with air spaces between them
- Lower epidermis: Single layer of cells on the lower surface
- Vein: A small vascular bundle running through the mesophyll
What to look for
- Upper and lower epidermis: Single layers of cells on the top and bottom surfaces of the leaf.
- Palisade mesophyll: A row of tall, tightly packed cells just under the upper epidermis, where most photosynthesis happens.
- Spongy mesophyll: Loosely arranged cells with air spaces between them, below the palisade layer.
- Midrib: The thick central vein that bulges out on the underside of the leaf.
- Xylem: Red-stained cells in the midrib, facing the upper side of the leaf.
- Phloem: Green-stained cells in the midrib, just below the xylem.
Questions and answers
What are the layers of a leaf cross section?
From top to bottom, a dicot leaf has an upper epidermis, a palisade mesophyll of tall packed cells, a spongy mesophyll with air spaces, and a lower epidermis. Veins with xylem and phloem run through the middle.
Why is the palisade layer on top?
The palisade cells sit just under the upper surface, where sunlight hits the leaf first. They are packed with chloroplasts, so most photosynthesis happens there.
Compare it
- Category
- Botany & Plants
- Scan magnification
- 20x
- Stain
- Safranin / Fast Green
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