Preparations of nuclei obtained following the final purification on 35% Percoll cushion by centrifugation. Preparations of nuclei from leaves of (A) tobacco, (B) potato and (C) apple obtained after the final purification on 35% Percoll cushion by centrifugation (step 6 in Figure 1A) contained only negligible amounts of debris. DAPI-stained nuclei (shown in blue) were observed with a fluorescence microscope using UV-light and debris observed simultaneously under normal light. The unstained structures are remaining contaminants. Scale bars, 10 μm.