Fig. 3. (A-E) Sequence of confocal optical sections (Z-series) taken at 1.25 µm stepped focus positions through a growing FM4-64-stained L. longiflorum pollen tube. Half of the ten-mage sequence is shown from the periphery to the median focal plane. (The other five images of the sequence (not shown) were very similar reflecting the radial symmetry of the pollen tube.) Pixel intensity values along a central transect through each image are shown. Bar, 15 µm.