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Is Stomata a Cell?

Published in Plant Anatomy 2 mins read

No, a stoma (plural: stomata) is not a single cell. A stoma is a pore, or tiny opening, found on the epidermis of leaves and other plant organs. It's composed of two specialized cells called guard cells. These guard cells regulate the opening and closing of the stoma, controlling gas exchange (like carbon dioxide intake and oxygen release) and water loss.

Understanding Stomata Structure and Function

  • Guard Cells: Two kidney-shaped guard cells surround each stomatal pore. These cells control the pore's size by changing their turgor pressure (internal water pressure). Increased turgor pressure causes the guard cells to swell and open the pore; decreased turgor pressure causes them to shrink and close the pore.

  • Stomatal Pore: The actual opening, the pore itself, is the space between the guard cells. This is where gas exchange occurs.

  • Subsidiary Cells (sometimes): Some stomata are surrounded by additional cells called subsidiary cells. These cells play a supporting role in stomatal function, but the guard cells are the primary players in regulating the pore.

Multiple sources confirm this structure:

Therefore, while guard cells are indeed individual cells, the stoma itself is a structure formed by these cells and the pore they create.