Confocal imaging of N. tabacum pollen tubes co-expressing SYP124T (truncated protein lacking the transmembrane domain) with full GFP-SYP124. A: Optical sections of a growing pollen tube. The cell exhibited no perturbations in apical morphology but protein localization exhibits a higher labelling in the plasma membrane further away from the sub-apical region (when compared to figure 1B). Numbers refer to the time interval (in seconds). Scale bar = 20 μm. B: Time course analysis of GFP fluorescence intensity in the first 20 μm of the pollen tube shown in A. Each line is representative of measurements of the fluorescent signal made in the lines/circles depicted in the diagram of figure 1E for 10 different pollen tubes. Growth rate measurements (μm.min-1) are displayed by the dashed lines. C: Distribution of average fluorescence intensity along the first 40 μm of the pollen tubes plasma membrane (n = 10) as depicted in the diagram. The distribution is significantly different (P = 3E-54) from GFP-SYP124 alone (compare with figure 1F) but very similar to GFPSYP121 and GFP-SYP122 (P = 0,01) (compare with figure 2D). Error bars not displayed for the sake of clarity.