LYCH dye moves with the nectar. Hand sections of extrafloral nectary (EFN) of Passiflora edulis 24 h after the application of the LYCH solution. (A, D, G) Transmission image. (B, E, H) LYCH fluorescence (485 nm excitation, 530 nm emission). (C, F, I) Overlay projection images of transmission and fluorescence. (A-C) EFN treated with distillated water. Note the absence of fluorescence; ep, epidermis; nt, nectar tissue; ap, adjacent parenchyma, *, vascular terminations. (E-I) Cuticle labelled. (G-I) Live EFN. (G) Autofluorescence of the cuticle and chloroplasts present in nectary tissue and adjacent parenchyma. (H, I) Positive result in the cuticle when only the emission of LYCH is selected. Nectar traces remain attached to the cuticle and cuticular flanges. Scale bars: 25 μm.