BY-2 confocal laser scanning microscopy. Tobacco BY-2 cells stably transformed with NtMMP1-GFP were analyzed by confocal laser scanning microscopy six days after sub-culturing. A: Untreated cells. B: Cells after treatment with 0.5 M KNO3 to induce plasmolysis. In each case, white light transmission is shown on the left, green fluorescence in the middle, and the overlaid images on the right. The scale bar indicates a distance of 50 μm.