Final answer:
The middle lamella is the shared cell wall material between adjacent plant cells, while plasmodesmata are channels that enable transport and communication between their cytoplasms.
Step-by-step explanation:
The layer of cell wall material shared between adjacent plant cells is known as the middle lamella. This layer is rich in pectins and helps to cement the primary walls of adjacent cells together. However, for the transport of materials between adjacent plant cells, structures known as plasmodesmata play a crucial role. These are channels that connect the cytoplasm of neighboring cells, allowing the transfer of water, nutrients, and other substances. Plasmodesmata are essential for intercellular communication and the distribution of resources throughout the plant.
The plant cell wall is a rigid structure external to the plasma membrane that provides protection, support, and shape to the cell. Unlike the prokaryotic cell walls, which mainly contain peptidoglycan, plant cell walls are composed of cellulose. This composition contributes to the firmness and structural integrity of plant tissues, as experienced when biting into a crunchy vegetable like celery.