Confocal images of the pistil injected with Fluo-3 (A-C) and control pistil (D-F). Pseudocolor images enhance the visualization of the incorporated Fluo-3 and show the intensity of fluorescence. Minimal fluorescence levels are visible as dark, whereas fluorescence levels of the highest intensity are indicated as white. (A-C) Optical sections of the stigma at stage 3 of flower development after Fluo-3 injection. The signal corresponding to the incorporated Fluo-3 is visualized as green. The highest levels of fluorescence are present in papillae cells (PP). (D-F) In the stigma of the pistil injected with control solution, no green fluorescence is present. Bars = 100 μm.