Home About us Contact
|
Home About us Contact | ||
|
|
||
Pratense L. (pratense + l)
Kinds of Pratense L. Selected AbstractsSeparation and determination of isoflavones in red clover by micellar electrokinetic capillary chromatographyBIOMEDICAL CHROMATOGRAPHY, Issue 9 2007Yu Zhang Abstract A micellar electrokinetic capillary chromatography (MECC) method has been developed for the determination of the four isoflavones, i.e. biochanin A, formononetin, genstein and daidzein in red clover (Trifolium Pratense L.). The effect of running buffer pH and concentration were investigated. An electrolyte composed of 30 mm borate, 20 mm sodium dodecyl sulfate (SDS) and 4 mg/mL HP- , -CD containing 5% (v/v) ethanol at pH 10.1 provides a satisfactory separation for all the analytes. The applied voltage was 25 kV, and the capillary temperature was kept constant at 25°C with a UV detection at 254 nm. The relative standard deviations (RSD) of the migration time and peak area were less than 1.73 and 3.94% (intra-day), and 2.29 and 4.38% (inter-day), respectively, under the optimized separation conditions. Regression equations revealed a good linear relationship between the peak area of each compound and its concentration. The contents of the four compounds in red clover were successfully determined with satisfactory repeatability and recovery. Copyright © 2007 John Wiley & Sons, Ltd. [source] Neighbouring monocultures enhance the effect of intercropping on the turnip root fly (Delia floralis)ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 3 2007Maria Björkman Abstract Knowledge of insect behaviour is essential for accurately interpreting studies of diversification and to develop diversified agroecosystems that have a reliable pest-suppressive effect. In this study, we investigated the egg-laying behaviour of the turnip root fly, Delia floralis (Fall.) (Diptera: Anthomyiidae), in an intercrop-monoculture system. We examined both the main effect of intercropping and the effect on oviposition in the border zone between a cabbage monoculture [Brassica oleracea L. var. capitata (Brassicaceae)] and a cabbage-red clover intercropping system [Trifolium pratense L. (Fabaceae)]. To investigate the border-effect, oviposition was measured along a transect from the border between the treatments to the centre of experimental plots. Intercropping reduced the total egg-laying of D. floralis with 42% in 2003 and 55% in 2004. In 2004, it was also found that the spatial distribution of eggs within the experimental plots was affected by distance from the adjoining treatment. The difference in egg-laying between monoculture and intercropping was most pronounced close to the border, where egg-laying was 68% lower on intercropped plants. This difference in egg numbers decreased gradually up to a distance of 3.5 m from the border, where intercropped plants had 43% fewer eggs than the corresponding monocultured plants. The reason behind this oviposition pattern is most likely that flies in intercropped plots have a higher probability of entering the monoculture if they are close to the border than if they are in the centre of a plot. When entering the monoculture, flies can pursue their egg-laying behaviour without being disrupted by the clover. As the final decision to land is visually stimulated, flies could also be attracted to fly from the intercropped plots into the monoculture, where host plants are more visually apparent. Visual cues could also hinder flies in a monoculture from entering an intercropped plot. Other possible patterns of insect attack due to differences in insect behaviour are discussed, as well as the practical application of the results of this study. [source] Effect of depth and width of cultivation and sowing date on establishment of red clover (Trifolium pratense L.) by rotary slot-seeding into grasslandGRASS & FORAGE SCIENCE, Issue 2 2010P. Komárek Abstract The effect of different combinations of time of sowing and depth and width of soil cultivation using a rotary slot-seeding machine to introduce red clover (Trifolium pratense) was determined for some characteristics of newly established red clover plants in a lowland Dactylis glomerata -dominated grassland in the Czech Republic. Sowing was carried out on four sowing dates in one growing season: 11 May; 21 June (after the first cut); 9 August (after the second cut); and 19 September. The experimental treatments consisted of all combinations of four depths (5, 10, 15 and 20 cm) and four widths (5, 10, 15 and 20 cm) of soil cultivation. Measurements were made of number of plants, weight and height of plants, weight and height of roots. Measurements at 2 months after sowing showed fewer seedlings for the 11 May sowing than for later sowing dates. The number of red clover plants increased as the row width was increased up to 15 cm, regardless of the depth of slot. Positive effects of slot width on weight and height of plants and weight and length of roots were recorded. A highly positive correlation was found between weight of plants and weight of roots. Width of row was the key factor for the successful establishment of seedlings into the existing sward by slot-seeding. A row width of 10 cm and depth of slot of 5 cm was considered a satisfactory combination. [source] Yield and stability of yield of single- and multi-clover grass-clover swards in two contrasting temperate environmentsGRASS & FORAGE SCIENCE, Issue 3 2009B. E. Frankow-Lindberg Abstract Diversity of clovers in grass-clover swards may contribute to greater herbage yields and stability of yield. This possible effect was evaluated in an experiment carried out over three harvest years at two contrasting sites, differing in precipitation and soil composition, using mixed swards containing either one, two or three clover species sown together with timothy (Phleum pratense L.) and meadow fescue (Festuca pratensis L.). The clover species were red clover (Trifolium pratense L.), white clover (Trifolium repens L.) and alsike clover (Trifolium hybridum L.) sown in various proportions in a total of ten treatments. All swards were fertilized with nitrogen with amounts that increased from year to year, and three harvests were taken in three consecutive years. There was a significant interaction between site and species mixture on total dry matter (DM) yields (range 27,32 tonnes ha,1) and DM yields of clovers (range 5,15 tonnes ha,1); red clover as a single species or in a mixture was superior at the dry site while multi-clover species mixtures were superior at the wet site. Alsike clover was the least productive species of clover. Stability of yield of clovers was generally higher by including white and red clover in the seed mixture but total DM yield was not. [source] Dietary cation,anion difference and cadmium concentration in grasses fertilized with chlorideGRASS & FORAGE SCIENCE, Issue 4 2007S. Pelletier Abstract High dietary cation,anion difference (DCAD) of grass herbage increases the occurrence of hypocalcaemia of dairy cows. Application of chloride fertilizer reduces DCAD of herbage but it could increase cadmium concentration in herbage. This study includes an experiment conducted in Australia and in Canada. A glasshouse experiment in Australia evaluated the effect of four rates of chloride application (0,240 kg ha,1) on values of herbage DCAD and cadmium concentration of above-ground plant material of timothy (Phleum pratense L.) and phalaris (Phalaris aquatica L.), harvested 6 weeks after sowing and grown on two soils that had received cadmium either as a contaminant in superphosphate (soil + Super) or in sewage biosolids (soil + Bio) along with respective control soils (soil 0 Super and soil 0 Bio). Application of chloride fertilizer decreased values of herbage DCAD by 349 mmolc kg,1 dry matter (DM). Herbage DCAD values were highest on the 0 Bio soil (739 mmolc kg,1 DM) and were not different among the three other soils. Species did not differ in herbage DCAD values. Cadmium concentration in the above-ground plant material was highest on the +Bio soil treatment (1·67 mg kg,1 DM) and was lower for the three other soil treatments. Above-ground plant material of phalaris had a higher cadmium concentration than that of timothy. Application of chloride fertilizer did not affect cadmium concentration in above-ground plant material, despite the high cadmium content of the soil on the +Bio treatment. The field experiment in Canada evaluated the effect of four rates of chloride application (0,144 kg ha,1) on cadmium concentration of a timothy-based grass sward grown on four sites with soils of different potassium content. Application of chloride fertilizer increased cadmium concentration of herbage at two of the four sites but the maximum increase in cadmium concentration was only 0·025 mg kg,1 DM. Chloride fertilizer can be applied to decrease forage DCAD with minimal risk of increasing Cd in the food chain. [source] Liquid chromatography coupled to nuclear magnetic resonance spectroscopy for the identification of isoflavone glucoside malonates in T. pratense L. leaves.JOURNAL OF SEPARATION SCIENCE, JSS, Issue 13 2004Eva de Rijke Abstract Previous studies revealed that the main isoflavones in extracts of leaves of T. pratense L. are biochanin A and formononetin, their 7- O -glucosides, and two glucoside malonate isomers of each of them. Since LC,MS(/MS) did not provide sufficient information to distinguish the glucoside malonate isomers, in the present paper LC,NMR as well as off-line two-dimensional NMR were used to obtain further structural information. Matrix solid-phase dispersion (MSPD) was applied to obtain sufficiently high analyte concentrations to perform LC,NMR. Stop-flow reversed-phase LC,NMR was performed using a gradient of deuterated water and deuterated acetonitrile. Off-line COSY and NOESY experiments were carried out to determine the positions of the glucose moiety on the flavonoid aglycone, and of the malonate moiety on the glucose. Based on the fragmentation patterns in MS/MS and the NMR spectra, the two formononetin glucoside malonate isomers were identified as 7- O -,-D-glucoside 6´´- O -malonate and 7- O -,-D-glucoside 4´´- O -malonate; i.e. they only differ in the substitution position of the malonate group on the glucoside ring. The biochanin A glucoside malonate isomers, however, have quite different structures. The main and later eluting isomer is biochanin A 7- O -,-D-glucoside 6´´- O -malonate, and the minor and earlier eluting isomer is 5-hydroxy-7-methoxyisoflavone 4´- O -,-D-glucoside 4´´- O -malonate: the positions of the methoxy group and the glucoside 6´´- O -malonate group on the flavonoid skeleton are interchanged. [source] On-line identification of phenolic compounds of Trifolium species using HPLC-UV-MS and post-column UV-derivatisationPHYTOCHEMICAL ANALYSIS, Issue 1 2007Johanne Polasek Abstract In an ongoing search for new active compounds in the field of phytoestrogens, a simple HPLC-UV-MS method has been developed in order to identify phenolic compounds. The study was performed on three different species of Trifolium (Leguminosae), namely Trifolium pratense L., T. pallescens Schreb. and T. alpinum L, collected in Switzerland. The comparison between the dichloromethane extracts revealed that the main aglycones are present in the three species whereas the methanolic extracts show different glycosides and malonate derivatives. The compounds of interest were mainly flavonoids, isoflavonoids and clovamides. Their identities were confirmed from retention times, UV and MS analyses and UV shifts following post-column derivatisation. Copyright © 2006 John Wiley & Sons, Ltd. [source] | ||||||||||