Flowers spectral characteristics of the invasive heliophyte species Erigeron canadensis l.

Purpose. Determination of spectral characteristics of Erigeron canadensis L. flowers to confirm the photoprotective effect of flavonoids and identify the raw material. Methods. The reflectance spectra were obtained in the range of 350–800 nm. The colorimetric parameters were determined in the CIE XYZ and CIE L*a*b* systems. For additional identification of flavonoids, the flowers were extracted with isopropanol and chemisorption of compounds from the extract on the surface of biocompatible aluminum oxide was carried out, followed by determination of spectral characteristics. Results. The selection of flowers was carried out at the flowering stage in an open meadow area near the Mokra Sura River (Novooleksandrivka, Dnipropetrovsk region), taking into account that the best development of heliophytes is observed under conditions of full illumination. For the first time, the reflectance and colorimetric characteristics of flowers were determined to determine the light-absorbing ability of horseweed as an invasive heliophyte species at the flowering stage. A defining feature of the reflectance spectra of flowers is the increase in the intensity of the maximum of UV-absorbing flavonoids compared to carotenoids and chlorophylls, which are localized in surface tissues. Differentiation of the spectral reflection curve of flowers turned out to be an effective way to increase the degree of distribution of the detected maxima. The studied flowers were also characterized by a specific set of colorimetric parameters. Flavonoids as a biologically active component were identified due to their chelating properties by chemisorption from a plant extract on biocompatible aluminum oxide and subsequent determination of the reflectance and colorimetric characteristics of the interaction product. Conclusions. Increased localization of ultraviolet-absorbing flavonoids in the surface tissues of flowers determines the increase in photoprotective ability as an adaptive enhancement of the reproductive system of the invasive heliophyte species. The results can be used to confirm the functional signs of invasiveness of alien plants, as well as to identify the raw material of horseweed and when using the resource potential of this species to obtain biologically active drugs.