Comparison of SG and DAPI using fluorescence microscopy. Chloroplasts isolated from seedlings at 20 days after imbibition stained with DAPI (B) or SG (D). (A, C) Brightfield images of the chloroplasts shown in (B) and (D). The contrast has been enhanced (inset in (B)) to accentuate fluorescence from the chloroplasts in the lower left quadrant. Scale bar is 10 μm. The exposure time for both (B) and (D) was 0.5 s. DAPI-stained chloroplasts were fixed in glutaraldehyde and SG-stained chloroplasts were not fixed.