Plant cells contain various solutes in the cytoplasm.Some of the solutes are dissolved in the large central vacuole.Some plant cells are normally in a medium of almost pure water.Because the cell wall is unable to expand to any great extent, water moves into the plant by osmosis and presses against the inside of the cell wall.This pressure, called turgor pressure, resists the further entry of water molecules into the cell. The cell is said to be turgid.If a plant cell is placed in a medium with lower water potential, water leaves the cell by osmosis.The protoplast (cell membrane, cytoplasm and cell contents) pulls away from the cellulose cell wall and the cell become plasmolysed.