31 Stomata

Leaf blades are dotted with openings called stomata (single stomate), especially on the undersides of leaves.

Stomata, which mean “mouths” in Greek, do indeed resemble tiny mouths surrounded by swollen lips.

The “lips” are actually individual cells (called guard cells) that can swell up to open the stomata or deflate to close them off.

By closing the stoma when the plant has enough carbon dioxide, the plant can preserve its water and prevent itself from drying out.

Stomata allows carbon dioxide in for photosynthesis and water vapour out for transpiration.

If the plant gets too dry they will close but this also stops photosynthesis.