What is the thin film that lies between the cell walls of adjacent plant cells called?

The thin film that lies between the cell walls of adjacent plant cells is known as the middle lamella. This structure primarily consists of pectins, which serve to cement together the walls of neighboring cells, providing stability and maintaining the integrity of the plant tissue. The middle lamella plays a crucial role in cementing cells together, allowing for intercellular communication and contributing to tissue cohesion.

While the primary wall is a component of an individual plant cell and provides structural support, it does not refer to the layer that exists between two adjacent cells. The cuticle, on the other hand, is a waxy layer that covers the surfaces of leaves and stems, serving to reduce water loss and protect against environmental damage, but it does not function as an intercellular adhesive. Lastly, pectin is a key component of the middle lamella but does not define the entire structure itself, as it is just one of the substances that compose this layer. Thus, the middle lamella is indeed the correct term for the film that lies between the cell walls of adjacent plant cells.