Horsetail Fern Mature Strobilus Autofluorescence
TRITC HYQ Bandpass Emission (Medium Bandwidth Excitation) Green Set
Autofluorescence emission intensity from a horsetail fern (Equisetum arvense) mature strobilus thin section. Endogenous autofluorescence in plant tissues arises from a variety of biomolecules, including chlorophyll, carotene, and xanthophyll. In the green excitation region, chlorophyll has an absorption band with a low extinction coefficient, but still produces a detectable level of fluorescence at emission wavelengths of 550 nanometers and above (green, yellow, orange, and red). For the fern reproductive tissue illustrated above, note the presence of autofluorescence emission intensity in the orange and red spectral regions, which is strongly reminiscent of a darkfield image.