Confocal images showing uptake of 2 μm FM4-64 into control and inhibitor-treated pollen tubes of P. meyeri within 12 min. All the pixel values did not include the peripheral region. A, A median focal plane confocal optical section of a control pollen tube; the bright field at one-third size appears as an insert. B, Pixel values along a central transect through the fluorescence image in A. C, A median focal plane confocal optical section of a pollen tube pretreated with 5 μg mL−1 BFA for 60 min; the bright field at one-third size appears as an insert. D, Pixel values along a central transect through the fluorescence image in C, showing that BFA stimulated the internalization of FM4-64 dye. E, A median focal plane confocal optical section of a pollen tube pretreated with 1 μm latrunculin B for 60 min; the bright field at one-third size appears as an insert. F, Pixel values along a central transect through the fluorescence image in E, showing latrunculin B inhibited the internalization of FM4-64 dye. G, A median focal plane confocal optical section of a pollen tube pretreated with 500 μm sodium azide for 60 min; the bright field at one-third size appears as an insert. H, Pixel values along a central transect through the fluorescence image in G, showing sodium azide blocked internalization of FM4-64 dye almost entirely. Bar = 25 μm.