Why is the cell between plant cells not solid?

The space between plant cells is not solid because it is filled with a gel-like substance called the middle lamella, primarily composed of pectin. This structure allows for flexibility and communication between adjacent cells while providing support. Additionally, the presence of plasmodesmata, which are microscopic channels, facilitates the transport of nutrients and signals, further preventing the space from becoming solid. This arrangement is crucial for maintaining the overall integrity and functionality of plant tissues.