Plant Cell Walls-2 
311 Syllabus

A typial plant cell has an external Wall, Cytoplasm and a Vacuole. The Plasmalemma is the boundary that separates the Cytoplasm and the Wall. The Tonoplast (Vacuole Membrane) is the boundary between the Vacuole and the Cytoplasm.	When the Cell Wall is removed the Prtotoplast is directly exposed to the outside emvironment. The Protoplast is the Plasmalemma and everything in side of it.
If all of the Protoplasts are destroyed, the Apoplast remains like a honey-comb. The Apoplast consists of the Cell Walls and Intercellular Spaces.	If all of the Cell Walls were removed and the cells touched one another they would constitute a Symplast (Sym means together)
The image above shows the thick and sturdy cell walls found in the Velamen of Orchids. The Protoplasts are gone and the Apoplast is all that remains.	Cells are interconnedcted by Plasmodesmata. The interconnected Protoplasts constitute the Symplast.

The Plasmodesmata are narrow channels in the cell wall. There is contuinity between the Cytoplasm and Plasma Membranes of adjacent cells. Consequently, the Protoplasts of each cell are in direct communion, and constitute the Symplast.

Molecules can pass from one cell to another via Plasmodesmata (Symplast).

Molecules can also move through the Apoplast but they must cross the Plasmalemma to enter the Symplast.

The movement of Molecules in the Apoplast is goverend by the rules of Chemistry and Physics.

The Movement of Molecules in the Symplast is also governed by the rules of biology.