Fig. 11. Movement of FM4-64-stained material in the apex of a L.
longiflorum pollen tube (average growth rate 21.9 µm/minute). (A-C)
Median section confocal images taken 2 seconds apart showing bulk movement of
FM4-64-stained material from a region 
5 µm behind the apex away from
the tip along the path of cytoplasmic streaming (arrows). (D-I) Images from
the same time series, taken 1 second apart, showing movement of FM4-64-stained
material from a region 25 µm subapically back towards the apex
(arrows). Diagrammatic interpretation of the `reverse fountain' path of
cytoplasmic streaming in a growing L. longiflorum pollen tube (J)
(see main text), and of the movement of FM4-64-stained material based upon
time-sequence imaging (see A-I) and FRAP experiments (see text for details)
(K). Bar, 20 µm.
