Scanning Electron Micrograph (SEM) of cut edge of a leaf, looking into cells which have been opened. Contents of the cells are seen through the thin membrane (the tonoplast membrane) which lines the large central vacuole of many plant cells. Most of the cells contain large chloroplasts, some bearing starch granules made by photosynthesis. Each cell is surrounded by a thin membrane and a thick wall of cellulose intervenes between these. These walls are rigid and offer structural support. Also visible within the cells are mitochondria, appearing as small rounded globules, and plasmodesmata, pit-like holes within the membranes of some cells. Magnification x2500.