Fig. 13. Quantitative analysis of the relationship between FM4-64 staining and oscillatory growth of a L. longiflorum pollen tube. (A) Growth rate for a pollen tube derived from confocal images of FM4-64 fluorescence. (B-D) Corresponding plots of average pixel value against time for the regions A-C defined in diagram (E). Heavy dashed lines show peak growth rate; grey boxed areas show the times when the apical 3-5 µm region is most distinctly defined from the more subapical FM4-64 staining (see Results and F). (E) Sample areas A-C: apical 1-3 µm, 5 µm and 10 µm subapically, respectively. (F) Graphs of pixel values along a central transect of the pollen tube are shown (as in Fig. 1) for images covering the growth period outlined by the cross-hatched area in A. The maximum and minimum rate growth phases of the period are indicated.