Light micrograph of an iris petal. This photograph shows the cells of a fresh petal, with cytoplasm (artificially stained purple) filling each of the cells. As the petal begins to wilt, water is lost and the cytoplasm retracts into the centre of each cell. Photo number B060/025 shows a wilted petal from the same flower. The many tiny particles visible within the cytoplasm are cell organelles known as plastids which produce the petal colour. Magnification: x150 at 35mm size.