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Melilotus, an annual or biennial herb, belongs to the tribe Trifolieae (Leguminosae) and consists of 19 species. As an important green manure crop, diverse Melilotus species have different values as feed and medicine. To identify different Melilotus species, we examined the efficiency of five candidate regions as barcodes, including the internal transcribed spacer (ITS) and two chloroplast loci, rbcL and matK, and two non-coding loci, trnH-psbA and trnL-F. In total, 198 individuals from 98 accessions representing 18 Melilotus species were sequenced for these five potential barcodes. Based on inter-specific divergence, we analysed sequences and confirmed that each candidate barcode was able to identify some of the 18 species. The resolution of a single barcode and its combinations ranged from 33.33% to 88.89%. Analysis of pairwise distances showed that matK+rbcL+trnL-F+trnH-psbA+ITS (MRTPI) had the greatest value and rbcL the least. Barcode gap values and similarity value analyses confirmed these trends. The results indicated that an ITS region, successfully identifying 13 of 18 species, was the most appropriate single barcode and that the combination of all five potential barcodes identified 16 of the 18 species. We conclude that MRTPI is the most effective tool for Melilotus species identification. Taking full advantage of the barcode system, a clear taxonomic relationship can be applied to identify Melilotus species and enhance their practical production. [ABSTRACT FROM AUTHOR]

Three new triterpene oleanane glycosides, melilotosides A, B, and C, and non-glycosylated soyasapogenol B were isolated from Melilotus officinalis (L.) Pall. (Fabaceae) roots. The structures of the glycosides were proved using chemical transformations and spectral data. Melilotoside A is soyasapogenol B 3-O-β-Dxylopyranoside; melilotoside B, soyasapogenol B 3-O-[β-D-galactopyranosyl-(1-2)-f-D-xylopyranoside]; melilotoside C, soyasapogenol B 3-O-[α-L-rhamnopyranosyl-(1-2)-β-D-galactopyranosyl(1-2)-β-Dxylopyranoside]. [ABSTRACT FROM AUTHOR]

Specific absorption rates (SAR) and specific utilization rates (SUR) of sodium, chloride, potassium, calcium, magnesium and phosphate ions were determined for Melilotus segetalis (Brot.) Ser. (annual sweetclover) grown under both control and salinized conditions (NaCI treatment of CE =15 dS m-1) for a complete life cycle with sequential harvests. The behaviour over time of the SARs and SURs of the mineral elements was in general correlated with relative growth rate (RGR) kinetics, with a parabolic trend during the vegetative phase and a progressive linear decrease during the reproductive stage. Salinity significantly reduced the SARs of K and Mg but did not affect the SARs of Ca and P during the vegeta- five phase. During the reproductive stage, however, the SARs of K, Ca and P of salt-stressed plants were higher than in control plants. The similar SARs of total cations (TC) found in control and salt-stressed plants may indicate compensatory mechanisms to maintain a constant total cation content. Salt-stressed plants showed lower SURs of K, Ca and P during the vegetative phase, and lower SURs of K and P but a higher SUR of Mg during the reproductive stage. A nutrient imbalance, caused by a lower root efficiency in absorbing K and Mg and a lower leaf efficiency in producing biomass per unit of K, Ca and P, apparently con- tributed to the salt-induced reduction in growth during the vegetative phase of M. segetalis. The switch to non- reduced, compensated growth during the reproductive phase may have been caused by a higher nutrient demand which increased the root efficiency in absorbing K, Ca and P and the leaf efficiency in utilizing Mg. [ABSTRACT FROM AUTHOR]

Annual sweetclover plants [Melilotus segetalis (Brot.) Ser.] were grown for a complete life cycle with and without saline (NaCl treatment of CE=15 dS m-1). Growth and partitioning analyses were performed. Sequential harvests (every 15 d) during the life cycle, and separation of plant material into roots, stems, petioles, leaves and reproductive structures were carried out Salt treatment reduced growth during the early and middle stages of the life of the plant, but did not significantly affect RGR in the reproductive phase. The root-shoot allometric coefficient of salinized plants in the generative phase decreased more than in control plants. We suggest that salinity-induced growth reduction in M. segetalis was primarily a result of a lower unit leaf rate (ULR) despite an increased leaf area ratio (LAR). Earlier flowering, higher biomass allocation to shoot and greater reproductive investment, but similar relative growth rate (RGR), were some of the main characteristics of salt-stressed plants compared to controls during the reproductive phase, these apparently being associated with increased sink strength caused by developing flowers and fruits. [ABSTRACT FROM AUTHOR]

Two triterpene glycosides of the oleanane series, melilotoside A and previously known adzukisaponin V, were isolated from the roots of Melilotus tauricus (L.) Pall. (Fabaceae). The structures of the glycosides were proved based on chemical transformations. Melilotoside A had the structure soyasapogenol B 3- O-β-D-glucouronopyranoside; adzukisaponin V, soyasapogenol B 3- O-[α-L-rhamnopyranosyl-(1-2)-β-Dglucopyranosyl-(1-2)-β-D-glucuronopyranoside]. [ABSTRACT FROM AUTHOR]

We describe specific primers that amplify nine microsatellite DNA loci from Melilotus alba and Melilotus officinalis, both invasive plant species (Fabaceae) throughout North America. Allelic diversity was slightly lower for M. alba than for M. officinalis, as was expected heterozygosity. For both species, heterozygote deficit was observed at several loci. Genotypic diversity was very high for both species; the 29 plant samples of each species all had different multilocus genotypes. These markers will be used to determine the origins of the sweetclover invasion in Alaska and to compare patterns of diversity between subarctic and lower latitude populations. [ABSTRACT FROM AUTHOR]