Differential interference contrast (DIC) light micrograph of the outer epidermis of an onion scale under plasmolysis. For better visualisation, a red onion variety was used here, which contains the red plant dye anthocyanin in the vacuoles. When a saturated sugar solution is added, there is a concentration balance in the intact cells, water migrates through the cell membranes to the outside, and the vacuoles shrink. This process is reversible. Magnification: x120 at a print width of 10 centimetres.