Figure 6.

Fragments of corolla petals L. album subsp. album imaged by a fluorescence microscope. (a,b) Light blue autofluorescence of phenolic acids (a) in epidermis cells in the cross section of the corolla tube, (b) in epidermis cells and capitate trichomes. (c–l) Yellowish secondary fluorescence of flavonoids observed after the application of aluminum trichloride under the Cy 5 filter. (c–e) Capitate trichomes containing flavonoids. (f,g) Different-length conical trichomes visible on the adaxial surface of the corolla tube with flavonoids in the apical part. (h) Non-glandular trichomes from the upper lip: flavonoid fluorescence in the cell walls. (i,j) Papillae on the upper lip containing flavonoids. (k,l) Epidermis cells from the upper lip with flavonoid content. Abbreviation: Ad adaxial epidermis, Ab abaxial epidermis. Scale bars: 100 µm (g,h), 50 µm (a), 30 µm (b,c,f,k), 20 µm (d,e,l), 10 µm (i,j).