Fig. 2. Plasmolysis of an FM4-64-loaded L. longiflorum pollen tube. (A) 5 minutes after applying standard medium with 0.3 M sorbitol and 2 µM FM4-64. The detector sensitivity was increased to show dye fluorescence associated with Hechtian strands at the apex (arrowhead). (B) Corresponding bright field image. Bar, 15 µm.