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Background. Dairy farming is one of the main segments in the agricultural sector of Murmansk Province. Expanding the range of cultivated legume fodder crops and their cultivars is one of the ways to comprehensively solve the problem of feed in the Kola Peninsula. Introduction of perennial legumes into the feed production practice will reduce the production cost of feeds and improve their quality.Materials and methods. Fodder galega, variable and yellow alfalfa (2005–2009), bird’s-foot trefoil (2006–2007), and sweet clover (2007–2008) were studied at the Polar Experiment Station of VIR. Weather conditions during the years of study differed in temperature and water regimes. Observations and records were made according to VIR’s guidelines. Statistical data processing included the calculation of the main variation parameters and the construction of a generalized linear model of the variance structure.Results. The data are presented on the study of the collection of four perennial fodder legumes in Murmansk Province, Russia, in 2005–2009. Alfalfa surpassed fodder galega, sweet clover and bird’s-foot trefoil in winter hardiness, height and bushiness, showed medium leafiness, and (for the entire study cycle) had low air-dry mass yield. Biennial bicarpic sweet clover stood out for its air-dry mass yield on average per year, had medium height and foliage, but low winter hardiness and bushiness. Bird’sfoot trefoil was significantly inferior to the rest of the studied crops in all agronomic characteristics. Galega had the highest leafiness; in winter hardiness, bushiness and plant height it was slightly inferior to alfalfa, and in yield to white clover. Seeds under the conditions of Murmansk Province can be obtained only from galega accessions.Conclusion. According to a set of agronomic characters, the most promising crop is fodder galega, especially its adapted naturalized accessions selected in 1991–1993.

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]

Summary: Melilotus species are used as green manure and rotation crops worldwide and contain abundant pharmacologically active coumarins. However, there is a paucity of information on its genome and coumarin production and function. Here, we reported a chromosome‐scale assembly of Melilotus albus genome with 1.04 Gb in eight chromosomes, containing 71.42% repetitive elements. Long terminal repeat retrotransposon bursts coincided with declining of population sizes during the Quaternary glaciation. Resequencing of 94 accessions enabled insights into genetic diversity, population structure, and introgression. Melilotus officinalis had relatively larger genetic diversity than that of M. albus. The introgression existed between M. officinalis group and M. albus group, and gene flows was from M. albus to M. officinalis. Selection sweep analysis identified candidate genes associated with flower colour and coumarin biosynthesis. Combining genomics, BSA, transcriptomics, metabolomics, and biochemistry, we identified a β‐glucosidase (BGLU) gene cluster contributing to coumarin biosynthesis. MaBGLU1 function was verified by overexpression in M. albus, heterologous expression in Escherichia coli, and substrate feeding, revealing its role in scopoletin (coumarin derivative) production and showing that nonsynonymous variation drives BGLU enzyme activity divergence in Melilotus. Our work will accelerate the understanding of biologically active coumarins and their biosynthetic pathways, and contribute to genomics‐enabled Melilotus breeding. [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.

Dicoumarol is a mycotoxin, that acts as a blood anticoagulant, is formed during the microbial action of molds and fungi in spoiled hay or silage containing high-coumarin plant. A HPLC-DAD method for determination of coumarins, including dicoumarol, coumarin, and 4-hydroxycoumarin was developed. Methanol and acetic acid were used as mobile phase with gradient elution. The simultaneous separation was performed using C18 type of stationary phase. The recoveries were 88.6 – 92.6 %, 91.8 – 95.0 %, and 89.7 – 94.1 % (evaluated for three concentration levels) for dicoumarol, coumarin, and 4-hydroxycoumarin respectively. The parameters of system suitability (repeatability of retention times and peak areas) were determined for evaluation of the method. The method showed a good linearity in the concentration range 0.7 – 100 μg.mL−1 for dicoumarol, 0.05 – 100 μg.mL−1 for coumarin and 4-hydroxycoumarin with correlation coefficients higher than 0.9885. Extracts of sweet clover herb, hay, and spoiled hay were subjected to HPLC-DAD analysis. The most abundant compound in sweet clover herb and hay extracts was coumarin. In spoiled sweet clover hay extract the 4-hydroxycoumarin was detected in addition. The formation of 4-hydroxycoumarin was also observed in the synchronous fluorescence spectra recorded at the wavelength difference of 90 nm (difference between emission and excitation wavelength).

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Background and Aims Submergence is a severe stress for most plants. Melilotus siculus is a waterlogging- (i.e. root zone hypoxia) tolerant annual forage legume, but data were lacking for the effects of partial and full submergence of the shoots. The aim was to compare the tolerance to partial and full submergence of 15 M. siculus accessions and to assess variation in traits possibly contributing to tolerance. Recovery ability post-submergence was also evaluated. Methods A factorial experiment imposed treatments of water level [aerated root zone with shoots in air as controls, stagnant root zone with shoots in air, stagnant root zone with partial (75 %) or full shoot submergence] on 15 accessions, for 7 d on 4-week-old plants in a 20/15 °C day/night phytotron. Measurements included: shoot and root growth, hyponastic petiole responses, petiole gas-filled spaces, leaflet sugars, leaflet surface hydrophobicity, leaflet gas film thickness and phellem area near the base of the main root. Recovery following full submergence was also assessed. Key Results Accessions differed in shoot and root growth during partial and full shoot submergence. Traits differing among accessions and associated with tolerance were leaflet gas film thickness upon submergence, gas-filled spaces in petioles and phellem tissue area near the base of the main root. All accessions were able to re-orientate petioles towards the vertical under both partial and full submergence. Petiole extension rates were maintained during partial submergence, but decreased during full submergence. Leaflet sugars accumulated during partial submergence, but were depleted during full submergence. Growth resumption after full submergence differed among accessions and was positively correlated with the number of green leaves retained at desubmergence. Conclusions Melilotus siculus is able to tolerate partial and full submergence of at least 7 d. Leaflet surface hydrophobicity and associated gas film retention, petiole gas-filled porosity and root phellem abundance are important traits contributing to tolerance. Post-submergence recovery growth differs among accessions. The ability to retain green leaves is essential to succeed during recovery. [ABSTRACT FROM AUTHOR]

Melilotus is an important genus of legume plants and an herbage with excellent nitrogen fixation; it can tolerate extreme environmental conditions and possesses important medicinal value. However, there is limited genetic information about the genus; thus, we analysed four chloroplast loci (rbcL, matK, psbA-trnH and trnL-F) and one nuclear region (ITS) to determine the genetic diversity of 199 accessions from 18 Melilotus species. The rbcL and matK sequences were highly conserved, whereas the trnL-F and ITS sequences contained variable and parsimony-informative sites. In our analyses of the single and combined regions, we calculated the pairwise distance, haplotype and nucleotide diversity and gaps and then constructed phylogenetic trees to assess the genetic diversity, and our results revealed significant variations among the different accessions. The genetic distance values were between zero and nine, and based on the combined regions, the highest frequency value was approximately four. Melilotus showed high haplotype and nucleotide diversity, particularly in the ITS sequences, with values of 0.86 and 0.0087, respectively. The single ITS sequence, psbA-trnH, and the combined matK+rbcL+trnL-F (MRT) and matK+rbcL+psbA-trnH+trnL-F+ITS (MRPTI) regions showed interspecific variation in the gap analysis. Phylogenetic trees calculated using ITS, psbA-trnH and MRPTI sequences indicated distinct genetic relationship in 18 species, and these species could be divided into two groups. By determining the genetic diversity of plants, we can evaluate the genetic relationships among species and accessions, providing a basis for preserving and utilizing the genetic resources of Melilotus. [ABSTRACT FROM AUTHOR]

Background and Aims Soil waterlogging adversely impacts most plants. Melilotus siculus is a waterloggingtolerant annual forage legume, but data were lacking for the effects of root-zone hypoxia on nodulated plants reliant on N2 fixation. The aim was to compare the waterlogging tolerance and physiology of M. siculus reliant on N2 fixation or with access to NO3-. Methods A factorial experiment imposed treatments of water level (drained or waterlogged), rhizobia (nil or inoculated) and mineral N supply (nil or 11 mm NO3-) for 21 d on plants in pots of vermiculite in a glasshouse. Nodulation, shoot and root growth and tissue N were determined. Porosity (gas volume per unit tissue volume) and respiration rates of root tissues and nodules, and O2 microelectrode profiling across nodules, were measured in a second experiment. Key Results Plants inoculated with the appropriate rhizobia, Ensifer (syn. Sinorhizobium) medicae, formed nodules. Nodulated plants grew as well as plants fed NO3-, both in drained and waterlogged conditions. The growth and total N content of nodulated plants (without any NO3- supplied) indicated N2 fixation. Respiration rates (mass basis) were highest in nodules and root tips and lowest in basal root tissues. Secondary aerenchyma (phellem) formed along basal root parts and a thin layer of this porous tissue also covered nodules, which together enhanced gas-phase diffusion of O2 to the nodules; O2 was below detection within the infected zone of the nodule interior. Conclusions Melilotus siculus reliant on N2 fixation grew well both in drained and waterlogged conditions, and had similar tissue N concentrations. In waterlogged conditions the relatively high respiration rates of nodules must rely on O2 movement via the aerenchymatous phellem in hypocotyl, roots and the outer tissue layers of nodules. [ABSTRACT FROM AUTHOR]

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]

Allodynia is a main symptom of the peripheral neuropathy induced by vincristine treatment. Theoesberiven F, a combination of Melilotus extract and proxyphylline, is currently used for the treatment of inflammatory conditions due to its potent anti-inflammatory and analgesic properties. The anti-allodynic effect of theoesberiven F on mechanical and cold allodynia in a rat model of vincristine-induced neuropathy was investigated in the present study. Intraperitoneal vincristine injections were administered to male Sprague-Dawley rats at a dose of 0.1 mg/kg/day over 12 days (5 days of injection, a 2-day cessation and 5 days of injection). Rats that were allodynic following the vincristine injections were randomly allocated into four groups. Normal saline was injected into rats in the control group. Theoesberiven F (0.1, 0.25 and 0.5 mg/kg) was administered to rats in the three experimental groups, respectively. Mechanical and cold allodynia were measured at preadministration and at 15, 30, 60, 90, 120, 150 and 180 min following the intraperitoneal administration of normal saline or theoesberiven F. The decreased paw withdrawal threshold induced by vincristine injection was increased by theoesberiven F administration. The increased withdrawal frequency to cold stimuli developed by vincristine was reduced by theoesberiven F administration. The results of this study suggest that the administration of theoesberiven F may be beneficial in reducing the mechanical and cold allodynia developed during vincristine treatment. [ABSTRACT FROM AUTHOR]

Melilotus comprises 19 species, while the phylogenetic relationships between species remain unclear. In the present work, three chloroplast genes, rbcL, matK, trnL-F, and one nuclear region, ITS (internal transcribed spacer) belonging to 48 populations of 18 species of Melilotus were sequenced and phylogenetic trees were constructed to study their interspecific relationships. Based on the phylogenetic tree generated in this study using rbcL analysis, the Melilotus genus is clearly monophyletic in the legume family. Both Bayesian and maximum-parsimony approaches were used to analyze the data. The nrDNA ITS provided more informative characteristics (9.8%) than cpDNA (3.0%). Melilotus contains two closely related groups, clade I and clade II. M. spicatus, M. indicus and M. segetalis have a close relationship. M. infestus, M. siculus and M. sulcatus are closely related. The comparing between molecular phylogeny and flower color classification in Melilotus showed that the flower color is not much informative for phylogenetics of this genus. [ABSTRACT FROM AUTHOR]

Background and aims: Plant productivity in drylands is frequently co-limited by water and nutrient availability, and thus is expected to be influenced by ongoing changes in rainfall regime and atmospheric nutrient deposition. Roadside grasslands are widespread worldwide, represent ecologically meaningful examples of highly dynamic anthropogenic ecosystems, and are well suited to investigate global change effects on plant performance. We evaluated the effects of changes in water and nutrient availability on the relative dominance and physiological performance of Bromus rubens, Carduus tenuifolius and Melilotus officinalis, which belong to contrasting functional groups (grasses, non-legume forbs and legumes, respectively). Methods: We conducted a factorial field experiment in two semiarid roadside grasslands in central Spain with the following factors: watering (no water addition vs. watering with 50% of the monthly total precipitation median) and fertilization (no fertilization vs. addition of 80 kg N ha year). The cover of the species evaluated, was surveyed over a 2-year period. Plant isotopic composition (leaf δC and δO) and nutrient concentrations (foliar N, P and K) were used to assess plant ecophysiological performance. Results: Carduus was able to cope with lower water availability levels through stomatal adjustments without a significant reduction in its relative dominance. The relative dominance of Bromus was negatively affected by even moderate water stress, although elevated nutrient deposition buffered the adverse impact of drought through a nutrient-mediated enhancement of plant water use efficiency. Increased nutrient availability strongly decreased the relative dominance of Melilotus, irrespective of water availability. Conclusions: Species-specific physiological mechanisms of adjustment to treatments suggest that plant communities in roadside grasslands will not respond as a unit to global environmental change. The characterization of species-specific responses to major global change drivers may improve predictions about the future dynamics of plant communities in novel ecosystems such as roadside slopes. [ABSTRACT FROM AUTHOR]

In ancient Chinese history, the Western Zhou Dynasty has long been renowned for having expanded its control and territory into many other states. However, historical documents and archaeological records of this period are limited; thus the early history of the Western Zhou Dynasty's operation in eastern China and its establishment of the Qi and Lu states have been unclear. The discovery of the Chenzhuang city site in Gaoqing County, Shandong Province, with chariot-horse pits, an altar and bronze vessels with inscriptions, adds a new line of evidence for studying the history of this period. However, with no direct evidence, the nature of the city site is controversial. Plant remains, especially a large number of sweet clover seeds, recovered from this site by systematic archaeobotanical methods provide an important source of information for research into the site's function. Considering that modern sweet clover is superior fodder for horses and the sweet clover seeds from the Chenzhuang site coexist with chariot-horse pits and horse remains, it is suggested these sweet clover seeds might represent the fodder of battle steeds. This suggestion supports the opinion of those who believe the Chenzhuang city site was once an important military city of the Western Zhou Dynasty in eastern China. [ABSTRACT FROM AUTHOR]

The aim of this research was to determine the forage yield and its components in blue melilot (Melilotus caerulea (L.) Desr.) grown in the western region of Turkey. Blue melilot seeds were collected during two years (2005-2006) at mature stage from grasslands (43.0 °N, 26 °E) of the Belovets village in Razgrad, the north-east of Bulgaria. This study was conducted during the 2006-2009 growing season (October-July) on xeralf soil with pH 6.8-7.1 at Field Crops Department experimental area (41.0 °N, 27.5 °E) in Agricultural Faculty of Namik Kemal University (Tekirdag), Turkey. The experimental design was a randomized complete block with four replicates. The plant height (cm), main stem diameter (mm), number of leaves per main stem, leaf length (cm), leaflet length (cm) and width (cm), green fodder yield (t ha-1), dry matter yield (t ha-1), crude protein (%) and fiber (%) were determined at the three growing stages such as 1/4 bloom, 1/2 bloom and full-bloom. It is concluded that green fodder yield (9.79-9.97 t ha-1) and dry matter yield (2.49-2.62 t ha-1) in the ½ bloom and full-bloom stages were determined to be higher than in the rest of the stage. Quality is high if the crop is cut in the 1/2 bloom stage. According to yield and other components, the blue melilot can be sown and cutting at 1/4 bloom, 1/2 bloom and full-bloom stages in the western of Turkey as well as in subtropical conditions. [ABSTRACT FROM AUTHOR]

• Aerenchymatous phellem (secondary aerenchyma) has rarely been studied in roots. Its formation and role in internal aeration were evaluated for Melilotus siculus, an annual legume of wet saline land. • Plants were grown for 21 d in aerated or stagnant (deoxygenated) agar solutions. Root porosity and maximum diameters were measured after 0, 7, 14 and 21 d of treatment. Phellem anatomy was studied and oxygen (O2) transport properties examined using methylene blue dye and root-sleeving O2 electrodes. • Interconnecting aerenchymatous phellem developed in hypocotyl, tap root and older laterals (but not in aerial shoots), with radial intercellular connections to steles. Porosity of main roots containing phellem was c. 25%; cross-sectional areas of this phellem were threefold greater for stagnant than for aerated treatments. Root radial O2 loss was significantly reduced by complete hypocotyl submergence; values approached zero after disruption of hypocotyl phellem below the waterline or, after shoot excision, by covering hypocotyl phellem in nontoxic cream. • Aerenchymatous phellem enables hypocotyl-to-root O2 transport in M. siculus. Phellem increases radially under stagnant conditions, and will contribute to waterlogging tolerance by enhancing root aeration. It seems likely that with hypocotyl submerged, O2 will diffuse via surface gas-films and internally from the shoot system. [ABSTRACT FROM AUTHOR]

This paper describes the range in coumarin concentrations at 90% flowering stage in 149 accessions belonging to 15 Melilotus species grown in a genetic resources field characterisation experiment in Adelaide, South Australia, and determines coumarin concentrations in Melilotus species grown at two contrasting field sites in South Australia (Kybybolite and Keith). In the genetic resources characterisation experiment, the mean coumarin content ranged from 0.06 to 0.753% of dry matter. M. segetalis, M. dentatus, M. sulcatus, M. siculus and M. infestus recorded low (0.06 to 0.113%) coumarin levels while moderate levels (0.332-0.753%) were registered in the other species. The coumarin levels at Kybybolite and Keith sites ranged from 0.095 to 0.943% amongst M. indicus accessions compared to M. siculus (0.007-0.100%) and M. sulcatus (0.007-0.810%). No coumarin was detected in a M. segetalis accession at these two sites. Accessions of M. siculus and an accession of M. segetalis (SA 36979) and of M. sulcatus (SA 40019) could be potential candidates as pasture legumes that can combine tolerance of both salinity and waterlogging, and acceptably low concentrations of coumarin. [ABSTRACT FROM AUTHOR]

Melilotus suaveolens Ledeb is a traditional medicinal plant for treating inflammation-related disease. This explores the inner anti-inflammatory mechanism of n-butanol extract from M. suaveolens Ledeb. Inflammatory cellular model was established by lipopolysaccharide intervention on RAW264.7 cell line. Levels of secreted cytokines TNF-α, IL-1β, IL-6, NO and IL-10 in supernatant, mRNA expression of TNF-α, COX-2, iNOS and HO-1, protein expression of COX-2 and HO-1, activation of NF-κB and ingredients in the extract were assayed by ELISA, real time quantitative PCR, western blot, immunocytochemical test and HPLC fingerprint test, respectively. As a result, the extract could not only markedly reduce the production of pro-inflammatory mediators to different extents by blocking NF-κB activation but also promote the release of anti-inflammatory mediator HO-1 significantly. Each 1 g extract contained 0.023531 mg coumarin and another two high polar ingredients, probably saponins. It can be concluded that the extract has similar effects on antagonizing pro-inflammatory mediators and cytokines like Dexamethasone, and has effects on promoting the production of anti-inflammatory mediators. [ABSTRACT FROM PUBLISHER]

The article presents a study which investigates the phenotypic features and species diversity of Phyllobacterium, Ensifer, and Rhizobium species from root nodules of sweet clover and alfalfa. The study selects and characterizes the bacterial isolates examples of the species from the belonging of phage types (PTs) 13 and 24. Results show that the phenotypes of the three species were uncommonly and highly effective with alfalfa, Medicago polymorpha, and sweet clover.

This study examines the impact of the exotic nitrogen-fixing legume Melilotus officinalis (L.) Lam. on native and exotic species cover in two Great Plains ecosystems in Badlands National Park, South Dakota. Melilotus is still widely planted and its effects on native ecosystems are not well studied. Melilotus could have direct effects on native plants, such as through competition or facilitation. Alternatively, Melilotus may have indirect effects on natives, e.g., by favoring exotic species which in turn have a negative effect on native species. This study examined these interactions across a 4-year period in two contrasting vegetation types: Badlands sparse vegetation and western wheatgrass ( Pascopyrum smithii) mixed-grass prairie. Structural equation models were used to analyze the pathways through which Melilotus, native species, and other exotic species interact over a series of 2-year time steps. Melilotus can affect native and exotic species both in the current year and in the years after its death (a lag effect). A lag effect is possible because the death of a Melilotus plant can leave an open, potentially nitrogen-enriched site on the landscape. The results showed that the relationship between Melilotus and native and exotic species varied depending on the habitat and the year. In Badlands sparse vegetation, there was a consistent, strong, and positive relationship between Melilotus cover and native and exotic species cover suggesting that Melilotus is acting as a nurse plant and facilitating the growth of other species. In contrast, in western wheatgrass prairie, Melilotus was acting as a weak competitor and had no consistent effect on other species. In both habitats, there was little evidence for a direct lag effect of Melilotus on other species. Together, these results suggest both facilitative and competitive roles for Melilotus, depending on the vegetation type it invades. [ABSTRACT FROM AUTHOR]

Identifying forage species that are productive in saline environments is an important research priority in many areas of the world affected by salinity. The salt and waterlogging tolerances of 19 species of Melilotus were evaluated in a series of glasshouse experiments. Measurements taken on each species included: dry matter (DM) production, root growth and development, shoot ion (Na+, K+ and Cl−) concentrations, root porosity, and in vitro estimates of nutritive value. Research on several species was restricted because of their potential as weed risks. Of the remaining species, M. siculus (syn. M. messanensis), an annual species, showed high relative salt and waterlogging tolerances, good DM production under non-stressed and stressed (saline and hypoxic) conditions, a high level of root porosity under stagnant conditions, low tissue ion (Na+, Cl−) concentrations, and a reasonable dry matter digestibility content (range 66–69%) under highly saline conditions. M. sulcatus ssp. segetalis and M. indicus were also identified as species with good DM production and tolerance to salinity and waterlogging stresses. Further weed risk assessments and field trials on these species are required before they can be promoted for use as pasture forages on saline areas. [ABSTRACT FROM AUTHOR]

Many recent studies suggest that more diverse communities are more resistant to invasion. Community characteristics that most strongly influence invasion are uncertain, however, due to covariation of diversity with competition and crowding. We examined separately the effects of species richness and dominance on invasion by an exotic legume, Melilotus officinalis, in intact, native Kansas grassland. We manipulated dominance of C4 grasses by reducing their abundance (i.e. ramet densities) by ∼25 and 50%. In addition, richness was reduced by removing species that were mainly rare and uncommon as might be expected with environmental changes such as drought and fragmentation. In both years of the study (2001–2002), invasibility, measured as peak establishment of Melilotus, was not affected by a 3-fold reduction in species richness, nor was there an interaction between loss of species and reduced dominance on invasion. In contrast, reductions in abundance of the dominants significantly reduced invasibility of the grassland plots in both years. Because the abundance of dominants was highly correlated with measures of competition (i.e. ratio of dominant biomass to total biomass) and crowding (total stem densities), this pattern was opposite to that expected if competition were indeed limiting invasion. Rather, invasion appeared to be facilitated by the dominant species, most likely because reduced dominance increased environmental stress. Our results suggest that dominance is the key community characteristic determining invasibility, because highly competitive and space-filling species can either enhance or reduce susceptibility to invasion depending on whether dominants create a more competitive environment or alleviate stressful conditions. [ABSTRACT FROM AUTHOR]

Invasion of nitrogen-fixing non-native plant species may alter soil resources and impact native plant communities. Altered soils may be the driving mechanism that provides a suitable environment to facilitate future invasions and decrease native biodiversity. We hypothesized that Melilotus invasion would increase nitrogen availability and produce soil microclimate and biochemical changes, which could in turn alter plant species composition in a montane grassland community. Our research addressed the effects of white and yellow sweet clover ( Melilotus officinalis and M. alba) invasion on soil characteristics and nitrogen processes in the montane grasslands in Rocky Mountain National Park. We sampled soil in replicate sites of Melilotus-invaded and control (non-invaded) patches within disturbed areas in montane grassland habitats. Soil composites were analysed for available nitrogen, net nitrogen mineralization, moisture, carbon/nitrogen (C : N ratio), texture, organic matter and pH. Data were recorded at three sample dates during the growing seasons of 1998 and 1999. Contrary to our expectations, we observed lower nitrogen availability and mineralization in invaded patches, and differences in soil moisture content and soil C : N. Soil C : N ratios were higher in invaded plots, in spite of the fact that Melilotus had the lowest C : N ratios of other plant tissue analysed in this study. These findings provide land managers of natural areas with a better perspective on the possibilities of nitrogen-fixing species impact on soil nutrient levels. [ABSTRACT FROM AUTHOR]

Exotic (nonnative) invasion, often fostered by anthropogenic disturbances, can be detrimental to the biodiversity of indigenous plant communities. We examined the impact of two exotic species, Melilotus officinalis and M. alba (yellow and white sweet clover) in the montane grassland community in Rocky Mountain National Park to determine (1) whether native and exotic plant diversity differs between patches within grasslands that are invaded by Melilotus species and patches that are not invaded (control patches) and (2) whether the presence of Melilotus species are associated with specific exotic species. Variables that were recorded included species richness, species composition, and percent cover in invaded and control patches at multiple spatial scales. The results showed that more exotic, annual/biennial, and forb species occurred within patches invaded by Melilotus species, while more native, perennial, and grass species occurred in nearby control patches. Moreover, the invaded patches had several exotic species that were not found in control patches, whereas certain native species were only found in control patches. In some instances, the presence of Melilotus in the native community appeared unrelated to disturbance; some colonies were in seemingly undisturbed meadows well beyond disturbance edges. The data also showed that Melilotus species spread beyond original mapped boundaries in a span of two seasons. [ABSTRACT FROM AUTHOR]

Respiration in support of N2 fixation by rhizobia in legume root nodules depends on an adequate supply of O2, but excessive O2 can damage nitrogenase, the key enzyme. The movement of O2 into and within the nodule is driven by gradients in the concentration of O2 or in the oxygenation of the O2‐carrier, leghaemoglobin. Steeper gradients may increase flux to the sites of respiration, but gradients also raise the possibility of inadequate O2 in some nodule zones and excessive O2 in others. No detailed study of O2 gradients in the interior of nodules has been published previously. Spectral changes in leghaemoglobin with oxygenation, previously used to measure the average O2 status of the nodule interior, were used to map longitudinal gradients in O2 and in respiratory capacity in the elongated nodules of alfalfa (Medicago sativa L.) and sweetclover (Melilotus officinalis L.). Variability among nodules under air in the magnitude and direction of internal O2 gradients was seen in both species. Despite consistently higher respiratory capacity near the meristematic tip, a majority of nodules had higher O2 towards the tip than towards the base. These results contrast with a previous report, apparently based on limited data, but they are consistent with anatomical and tracer studies showing higher gas permeability near the tip. [ABSTRACT FROM PUBLISHER]

Examines the mechanisms of Nod factor perception and signaling transduction of Medicago truncatula. Identification of a new locus and nodulation-signaling pathway 2; Reduction of root hair deformation response; Absence of infection and cortical cell division following Sinorhizobium meliloti inoculation.

Examines the importance of oxygen limitation response on Sinorhizobium meliloti survival in the soil environment. Characterization of molecular response of free living S. meliloti to oxygen limitation; Involvement of FixL/FixJ in the regulation of the oxygen limitation response; Isolation of S. meliloti.

Offers a look at a study that reported chemical and biological data supporting the identification of lumichrome as the described Sinorhizobium meliloti factor that increases alfalfa root respiration. Materials and methods; Biological tests with lumichrome; Optimization of the production of compound D; Purification of compounds D and Y; Identification of compounds D and Y; Biological activity of lumichrome; Discussion.

The allocation of biomass and mineral elements Na, K, Ca, P, N, Fe, Cu, Mn and Zn) during the ontogenetic cycle of annual sweetclover (Melilotus segetalis (Brot.) Ser.) growing under favourable and saline conditions has been studied. Plants were grown in a glasshouse, in pots with siliceous substrate- and watered with Hoagland solution. Half were salinized by adding 170 mol m-3 NaCl (15 dS m-1 to the solution. Eleven harvests at 15 d intervals measured the dry weight distribution within the plant and the mineral composition. Allocation relative to biomass (ARB) in each plant organ, both under favourable and salt-stress conditions, was calculated For each mineral element. Biomass and mineral elements were allocated independently within M. segetalis and the general pattern changed with age and was affected by salinity. Salt-stressed plants were smaller and invested proportionately more biomass in leaves. Na was accumulated in roots of young plants and excluded from leaves and fruits, whereas K was depleted from roots and accumulated in leaves and fruits. immobile Ca accumulated in leaves; with age. Phloem-mobile P and N were translocated to flowers and fruits. Fe, Cu and Zn were diluted in leaves and not affected by salt, whereas Mn concentration increased with age and salinity. The switch to reproduction and increased demand fur nutrients induced drastic changes in the allocation pattern of mineral elements. Salinity induced a re-allocation of biomass and mineral elements in all plant organs except the reproductive structures, as part of a whole-plant response to minimize salt toxic effects, to achieve osmotic adjustment, to present the reproductive output, and to compensate nutrient imbalance. [ABSTRACT FROM AUTHOR]

Twenty one samples of honey from the northeast of La Pampa province were analized using the techniques proposed by Louveaux et al. (1978). Thirty four types were identified. Eight samples have a mixed floral origin and 13 were monofloral from Prosopis sp. (one sample) and Melilotus sp. (12 samples). The pollen spectrum shows a transition area between the "pampeana" and the "espinal" regions. The characteristic pollen combinations are discussed. [ABSTRACT FROM AUTHOR]

Presents information on a study which analyzed the pathway of rhizopine degradation, with emphasis on Sinorhizobium meliloti strains. Information on rhizopine catabolism assays; Cloning of the inositol locus from Sinorhizobium meliloti 1021; Findings of the study.

Studies nitrogen mineralization and crop uptake of 15N labelled red clover and yellow sweetclover plant fractions. Measurement of 15N recovery in spring wheat and lolium perenne; Condition when maximum nitrogen mineralization was observed; Contribution of different plant parts and age in nitrogen mineralization.

The acidic and calcareous populations of Melilotus alba behave differently when grown in competition than when grown in isolation from each other. Thus, the acidic population which did well in both calcareous and acidic media in competition-free cultures, showed good growth yield in acidic soils only when in competition with the calcareous population. Further, the differences observed between the two populations in competition-free experiments became more pronounced when grown mixed. The time of introduction of either of the two populations into the mixture affects the final dry weight yield of the shoot, depending upon the soil type. In mixed cultures of the two populations, the calcareous population grown in an acidic soil and the acidic population grown in a calcareous soil responded by mortality of individuals, especially when the second population in each case was introduced earlier into the mixture. [ABSTRACT FROM AUTHOR]

The article focuses on observations on the latest of the Middlesex, England series of chalk pits. The floor area was dominated by Melilotus officinalis in July 1933. The fluctuations may be due to the biennial habit and by 1942, it was hard to find plants in the pit. Melilotus flourishes on cliffs which are constantly eroded. Lotus corniculatus was not seen to be attacked by rabbits and it exploits crevices below the upper weathered chalk. The Medicago lupulina is a rapid colonizer of bare chalk but is susceptible to drought. Plants colonizing the Home Ground range include Achillea millefolium, Agrostis stolonifera and Plantago media.

Weed seeds of sweet clover (Melilotus indica L.) were evaluated alone or in combination with sodium chloride (NaCl). for their effects on germination and seedling growth of rice. The seed germination of rice was affected significantly when weed seeds were incorporated with 0.4% NaCl solution. It was observed that weed seeds alone and with 0.2%.NaCl had significant effect on shoot length. Similarly, a 0.4% NaCl alone or in combination with weed seeds reduced the shoot length. The root length was also reduced by application of weed seeds alone and in combination with NaCl. It was also observed that root length was affected more than the shoot. [ABSTRACT FROM AUTHOR]

Discusses the disadvantages of nitrogen fixing plants such as sweetclover. Effects of yellow sweetclover on the grasslands of the Northern Great Plains; Role of sweetclover in nitrogen fixation; Evidence that sweetclover can make a significant contribution to the nitrogen budget of associated rangeland plants.

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]

Sinorhizobium meliloti participates in a nitrogen-fixing symbiosis with legume plant host species of the genera Medicago, Melilotus, and Trigonella. We recently identified an S. meliloti two-component sensory histidine kinase, CbrA, which is absolutely required to establish a successful symbiosis with Medicago sativa (K. E. Gibson, G. R. Campbell, J. Lloret, and G. C. Walker, J. Bacteriol. 188:4508-4521, 2006). In addition to having a symbiotic defect, the cbrA::Tn5 mutant also has free-living phenotypes that suggest a cell envelope perturbation. Because the bases for these phenotypes are not well understood, we undertook an identification of CbrA-regulated genes. We performed a microarray analysis and compared the transcriptome of the cbrA::Tn5 mutant to that of the wild type. Our global analysis of gene expression identified 162 genes that are differentially expressed in the cbrA::Tn5 mutant, including those encoding proteins involved in motility and chemotaxis, metabolism, and cell envelope function. With regard to those genes with a known role in symbiosis, we observed increased expression of nine genes with overlapping functions in bacterial invasion of its host, which suggests that the mutant could be competent for invasion. Since these CbrA-repressed genes are vital to the invasion process, it appears that down-regulation of CbrA activity is important at this stage of nodule development. In contrast, our previous work showed that CbrA is required for bacteria to establish themselves within the host as nitrogen-fixing symbionts. Therefore, we propose a model in which CbrA functions as a developmental switch during symbiosis. [ABSTRACT FROM AUTHOR]