All moral rights asserted. Recolouring or alteration of the image is prohibited without permission. Bright field light micrograph of a thin section of red onion cells. The whole of each cell vacuole is filled with the violet pigment anthocyanin after this tissue was placed in a salt (sodium chloride) solution. The dilute (hypotonic) salt solution caused water to diffuse into the cell cytoplasm, leading to the cells to become turgid. If placed in a concentrated (hypertonic) salt solution the cells would undergo plasmolysis (shrinkage). This is the first image in a sequence showing red onion cells undergoing plasmolysis and then recovering back to turgor. See C056/2334 - C056/2340 for the sequence. Magnification: x200 when printed at 15 centimetres wide.