Bulliform Cells (Leaf Rollers)

Big bubbles on a grass leaf

Bulliform cells are found on the top side of leaves of grasses and some of their relatives, like corn and rice.

They are much bigger than the other skin cells around them. They have thin walls and are mostly filled with a big bag of water. They sit in little groups, often in grooves that run along the leaf.

Rolling the leaf to save water

Scientists think bulliform cells work like little water balloons that help the leaf fold:

• On a dry day, they lose water and shrink, so the leaf can fold or roll up.
• A rolled leaf has less surface open to the hot sun and dry wind, so it loses less water.
• When there is water again, they fill back up, and the leaf opens flat.

Bulliform cell quiz