Figure 3: The fluorescence of pharmaceutical valuable secretory cells of female flower cone bracts from Humulus lupulus L. ((a), (b), (c)) Stereomicroscopic images of multicellular resinous glands which single cells are liberated and named as lupulin; (d) fluorescence of multicellular gland under UV-light of luminescence microscope Leica D 6000 B; (e) the fluorescence spectra of the gland recorded by microspectrofluorimeter MSF-1; (f) common image of glandular surface fluorescing under laser-scanning confocal microscope Leica TCS SP-5 (laser excitation 405 nm) in green-yellow and (g) ROI of the image (marked by blue and violet rings, numbers 1, 2, and 3, bar = 100 μm); (h) the fluorescence spectra of the ROI marked as 1, 2, and 3 on image (g); (i) the fluorescence spectra of water bitter acid-containing extract from glands (1 : 10 w/v) registered by spectrofluorometer Perkin Elmer 350 MPF-44B in 0.5 cm3 cuvette, excitation 360 nm.