Fig. 4. FM4-64-uptake time course in a growing L. longiflorum pollen tube. (A-J) Median confocal fluorescence images at increasing times (minutes) after addition of FM4-64 (2 µM in 115% standard medium). To avoid osmotic perturbation, pollen tubes were pretreated with 115% medium before dye application. Inserts show bright field images at 1/3 size. Bar, 20 µm.