Bulliform Cells

Bulliform cells are large, bubble-shaped dermal tissue cells often found on the upper epidermis of monocot leaves. They are used to fold and unfold leaves. This occurs in response to the value of turgor pressure within the cell: when the bulliform cells lose turgor pressure, they become flaccid and shrivel, causing the leaves to fold inwards. This mechanism is used in monocots to prevent water loss through evaporation in xerophytic conditions, as the bulliform cells share the same tissue layer as that of many stomata.