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Identifying sustainable resources of natural fibers is essential due to their high demand in industrial applications such as automotive and biomedical materials. Two alternative fibers obtained from canola and sweet clover stalks were characterized for their properties using energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), contact angle, and tensile test. Hemp and flax fibers, both in use as industrial fibers, were also characterized as conventional fibers. Results showed that all the fibers had the same chemical elements (carbon, oxygen, magnesium, and potassium) and chemical bonds. The crystallinity index for the alternative fibers ranged from 62 to 71%, which was close but lower than the conventional fibers (82% for hemp and 80% for flax). The thermal stability of the alternative fibers was around 220 °C, close to the conventional fibers (230 °C). The alternative fibers had contact angles of less than 90°, showing high surface energy. Since the alternative fibers had a low Young's modulus and tensile strength (5.57–8.52 GPa and 57.45–71.26 MPa, respectively), they are suitable for some specific applications in the biomedical industry. In contrast, conventional fibers are suitable where a higher stiffness and strength is required. [ABSTRACT FROM AUTHOR]

White sweet clover (Melilotus albus) cultivation, despite its many positive features such as the high yield of green mass, as well as protein content, is currently not widespread. This study aimed to determine the effect of the different sowing densities (500, 1000, and 1500 seeds per m2) and harvesting at different growth stages (before budding, budding, and full flowering) on the quality of fodder from the white sweet clover (Adela variety). The field experiment was carried out in the years 2018–2020 in a split-plot design. Plant biometric measurements, green and dry yield, the content of total protein, crude fat, crude fiber, ash, macro and microelements, and coumarin content were determined. The results show that an increase in the sowing density significantly increased the plant population after emergence and green and dry matter. However, it does not affect the total protein, crude fat, crude fiber, ash, macro and microelements, and coumarin content. Harvesting plants at the flowering stage increased plant height and green fodder yield. Plants harvested at the prebudding phase were characterized by the highest share of leaves (40.3%) and were the most abundant in protein (21.7%) and minerals (ash content 12.71%). Unfortunately, sweet clover at this growth stage contained the highest level of coumarin, which limits its use in animal feed. [ABSTRACT FROM AUTHOR]

Melilotus albus and Melilotus officinalis are widely used in forage production and herbal medicine due to the biological activity of their coumarins, which have many biological and pharmacological activities, including anti-HIV and anti-tumor effects. To comprehensively evaluate M. albus and M. officinalis coumarin content (Cou), morphological variation, and molecular phylogeny, we examined the Cou, five morphological traits and the molecular characterization based on the trnL-F spacer and internal transcribed spacer (ITS) regions of 93 accessions. Significant (p < 0.05) variation was observed in the Cou and all five morphological traits in both species. Analysis of population differentiation (Pst) of the phenotypic traits showed that powdery mildew resistance (PMR) had the greatest Pst, meaning that this trait demonstrated the largest genetic differentiation among the accessions. The Pst values of dry matter yield (DMY) and Cou were relatively high. Biplot analysis identified accessions with higher DMY and higher and lower Cou. Analysis of molecular sequence variation identified seven haplotypes of the trnL-F spacer and 13 haplotypes of the ITS region. Based on haplotype and sequence analyses, the genetic variation of M. officinalis was higher than that of M. albus. Additionally, ITS sequence analysis showed that the variation among accessions was larger than that among species across three geographical areas: Asia, Europe, and North America. Similarly, variation among accessions for both the trnL-F and ITS sequences were larger than the differences between the geographical areas. Our results indicate that there has been considerable gene flow between the two Melilotus species. Our characterization of Cou and the morphological and genetic variations of these two Melilotus species may provide useful insights into germplasm improvement to enhance DMY and Cou. [ABSTRACT FROM AUTHOR]