LYCH dye efficiently stains the reabsorbed nectar pathway through nectary tissues. Hand sections of floral nectaries (FN) of Cucurbita pepo 24 h after the introduction of the LYCH solution onto nectar standing at the flower base. (A, D) Transmission image. (B, E, G, H) LYCH fluorescence (485 nm excitation, 530 nm emission). (C, F, I) Overlay projection images of transmission and fluorescence. (A-C) FN treated with distillated water instead of LYCH solution. Note the absence of fluorescence (B,C). (D-I) Different regions of the same nectary: labelled cells in epidermis (ep) (E-G), nectary tissue (nt), inner parenchyma and vascular bundles (*) (F, H-I). (G) Epidermis in frontal view; arrowhead, stomata. Scale bars: 25 μm.