Isolation and identification of novel pyranoanthocyanins from black carrot (Daucus carota L.) juice     

Schwarz M  Wray V  Winterhalter P 《Journal of agricultural and food chemistry》2004,52(16):5095-5101

Six novel pyranoanthocyanins were identified by HPLC-ESI-MSn in black carrot (Daucus carota L. ssp. sativus var. atrorubens Alef.) juice. The two major compounds, namely, the vinylcatechol adducts of cyanidin 3-O-(6-O-feruloyl-beta-D-glucopyranosyl)-(1-->6)-[beta-D-xylopyranosyl-(1-->2)]-beta-D-galactopyranoside and cyanidin 3-O-[beta-D-xylopyranosyl-(1-->2)]-beta-D-galactopyranoside, respectively, were isolated by a combination of high-speed countercurrent chromatography with semipreparative HPLC. Their structures were fully elucidated by means of one- and two-dimensional NMR spectroscopy and high-resolution mass spectrometry. The four remaining pigments were characterized as the vinylphenol and vinylguaiacol adducts of cyanidin 3-O-[beta-D-xylopyranosyl-(1-->2)]-beta-D-galactopyranoside, the vinylguaiacol adduct of cyanidin 3-O-(6-O-feruloyl-beta-D-glucopyranosyl)-(1-->6)-[beta-D-xylopyranosyl-(1-->2)]-beta-D-galactopyranoside, and the vinylcatechol adduct of cyanidin 3-O-(6-O-sinapoyl-beta-d-glucopyranosyl)-(1-->6)-[beta-D-xylopyranosyl-(1-->2)]-beta-D-galactopyranoside. These compounds are formed during storage of the juice through the direct reaction of either caffeic, ferulic, or coumaric acid with the respective genuine anthocyanins.  相似文献   

Sedimentary aggregates in the Peoria Loess of Nebraska, USA     

Joseph A. Mason  Peter M. Jacobs  Richard S. B. Greene  W. D. Nettleton 《CATENA》2003,53(4):574

Loess grain size data used to infer transport direction or wind strength are generally derived from vigorously disaggregated samples. However, these data may not adequately represent the effective particle size distribution during loess transport, if the transported dust contained aggregates of fine-grained material. Thin sections of minimally altered C and BC horizons in the late Pleistocene Peoria Loess of Nebraska, USA, indicate the presence of aggregates with diameters of 30–1000 μm. The larger aggregates (>250 μm) are unlikely to have been transported, and are interpreted as the result of soil faunal activity and other pedogenic processes after deposition. Aggregates smaller than 250 μm could have a similar origin, but laser diffraction particle size analysis suggests that many are sedimentary particles. Comparison of minimally and fully dispersed particle size distributions from each sampling site was used to estimate the modal diameter of aggregates. The aggregate modal diameter becomes finer with decreasing loess thickness, representing increasing distance from the source. A similar trend was observed in the modal diameter of fully dispersed particle size distributions, which represents the mode of sand and silt transported as individual grains. We interpret both trends as the result of sorting during transport, supporting the interpretation that many of the aggregates were transported rather than formed in place. Aggregate content appears to increase with distance from the source, explaining a much more rapid downwind increase in clay content than would be expected if clay were transported as particles smaller than 2 μm diameter. Although the Peoria Loess of Nebraska contains sedimentary aggregates, many of the coarse silt and sand grains in this loess were transported as primary particles, were thoroughly exposed to sunlight and are potentially well suited for luminescence dating.  相似文献   

Diallyl-disulphide to reduce the numbers of sclerotia of Sclerotium cepivorum in soil     

Andrew R. Entwistle  Peter R. Merriman  Herbie L. Munasinghe  Patricia Mitchell 《Soil biology & biochemistry》1982,14(3):229-232

A single injection of 0.2 ml diallyl disulphide (DADS) at 0.156% (v/v) into soil containing naturally-produced sclerotia of Sclerotium cepivorum and maintained in the laboratory at 15°C stimulated sclerotial germination and reduced sclerotial numbers by 67%; ungerminated sclerotia remained viable. Higher concentrations of DADS had no additional effect except that at 20% (v/v), germination was slightly inhibited. A similar reduction in sclerotial numbers was obtained when the mixture of soil and sclerotia was exposed to DADS vapour. Four, monthly applications of DADS at 0.2 ml 0.15% (v/v) per application did not give a further reduction.The effect of DADS was temperature dependant, with a reduction in sclerotial numbers of 65 and 9% at 15 and 5°C respectively.  相似文献   

Species concepts and systematics of domesticated cereals     

Dr. Johannes M. J. De Wet 《Genetic Resources and Crop Evolution》1981,29(1):177-198

Summary Cultivated cereals are domesticated grasses. Wild progenitors of domestic cereals are aggressive natural colonizers and often become weedy in man disturbed habitats. Hybridization between cultivated cereals and their close wild relatives gives rise to mimetic cereal weeds that often accompany the domestic species well beyond its natural range. Similar weeds may also evolve from abandoned cultivars as a result of mutations that restore their ability for natural seed dispersal. Cultivated complexes of domestic species are typically variable. Man selects and isolates phenotypes to suit his fancies, with the result that different phenotypes of a cereal are often grown for different uses in the same village, and adjacent villages often grow different phenotypes for similar uses. Conventional species concepts do not hold for domestic species. It is proposed that wild, weed and cultivated complexes of individual domestic species be recognized respectively as subspecies. Major discontinuities in variation within the weed or cultivated subspecies are then identified as races without formal taxonomic recognition.

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Artbegriff und Systematik bei domestizierten Getreiden

Zusammenfassung Kultivierte Getreide sind domestizierte Gräser. Die wilden Vorfahren der domestizierten Getreide sind aggressive natürliche Besiedler und werden oft zu Unkräutern in vom Menschen beeinflußten Standorten. Bastardierung zwischen kultivierten Getreiden und ihren wilden Verwandten läßt mimetische Getreideunkräuter entstehen, die oft die domestizierten Arten außerhalb ihres natürlichen Verbreitungsgebietes begleiten. Ähnliche Unkräuter können sich auch aus aufgegebenen Sorten entwickeln als ein Ergebnis von Mutationen, die ihre Fähigkeit zur natürlichen Samenausstreuung wiederherstellen. Kultivierte Komplexe domestizierter Arten sind in typischer Weise variabel. Der Mensch selektiert und isoliert Phänotypen nach seinen Vorstellungen mit dem Ergebnis, daß verschiedene Phänotypen eines Getreides oft zu verschiedenen Zwecken im selben Dorf angebaut werden, und benachbarte Dörfer oft verschiedene Phänotypen für ähnliche Zwecke kultivieren. Der herkömmliche Artbegriff bewährt sich nicht bei domestizierten Arten. Es wird vorgeschlagen, daß Wild-, Unkraut- und Kulturformen einer domestizierten Art als entsprechende Unterarten angesehen werden. Größere Gruppen innerhalb der Unkraut- oder Kultur-Unterart sollten als Rassen ohne formale taxonomische Bezeichnung gehandhabt werden.

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Peatland water chemistry in Central Ontario in relation to acid deposition     

Peter J. Blancher  Donald K. McNicol 《Water, air, and soil pollution》1987,35(3-4):217-232

Thirty-one peatlands from two areas of central Ontario were sampled to assess the influence of acid deposition on peatland water chemistry. Factor analysis differentiated peatland water chemistry along three major axes of chemical variation, interpreted as axes of organic concentration, mineral concentration, and deposition influence. Water from the surface mats had a higher organic concentration than water from open pools. Mineral influence in peatland waters was reflected by higher concentrations of Ca, Mg, Na, and silica in fen pools compared to bog pools. The influence of high acid deposition in the Wanapitei study area was indicated by high concentrations of sulphate, Ni, Mn, and Cu, and lower pH compared to an area that has received less acidic deposition (Ranger). Regression analyses indicated that H⁺ variation in bogs could be largely explained by organic C concentration, but that sulphate concentration was also positively associated with acidity, while Ca was negatively associated with acidity.  相似文献   

Foliar potassium status explains Douglas fir response to nitrogen fertilization in the inland Northwest,USA     

Peter G. Mika  James A. Moore 《Water, air, and soil pollution》1990,54(1):477-491

Despite apparently inadequate N levels throughout the Inland Northwest of the United States, trees on some sites showed no increased growth 6 yr after N fertilization. Nor did higher N application rates consistently produce higher response. These facts indicated that other factors are limiting tree growth at these sites. Results suggest that K status is one important factor, influencing N fertilization response in the following general ways; (1) for stands with low pretreatment foliar K levels, the amount and duration of growth response are reduced, and higher N fertilizer rates produce less response; and (2) for all stands, growth response declines when foliar K decreases after N fertilization.  相似文献   

Critical loads for nitrogen deposition on forest ecosystems   总被引：2，自引：0，他引：2  

E. - D. Schulze  W. De Vries  M. Hauhs  K. Rosén  L. Rasmussen  C. -O. Tamm  J. Nilsson 《Water, air, and soil pollution》1989,48(3-4):451-456

Critical loads for N deposition are derived from an ecosystem's anion and cation balance assuming that the processes determining ecosystem stability are soil acidification and nitrate leaching. Depending on the deposition of S, the parent soil material, and the site quality critical N deposition rates will range between 20 to 200 mmol m^?2 yr^?1 (3 to 14 kg ha^?1 yr^?1) on silicate soils and reach 20 to 390 mmol m^?2 yr^?1 (3 to 48 kg ha^?1) on calcareous soils.  相似文献   

Einfluß der Fließstreckenlänge auf die Bodenumlagerung innerhalb einer erosionsgeschützten Kleinparzelle     

Heinz Peter Schrey 《植物养料与土壤学杂志》1987,150(4):235-240

Dependence of erosion from flow length within an erosion-protected plot On an Udalf derived from loess different micro-reliefs were formed to reduce erosion. Their effects on the spatial distribution of sand contents on bare soil after one vegetation period are described. At first erosion caused residuals of sand on unflooded areas and corresponding accumulation of finest material on flooded ones. Beds without flow barriers showed reduced clay and silt contents in the upper layer of about 2 mm. On beds with small dams there were no soil losses from the catchment areas between these flow barriers visible. Secondly the enriched sand was moved, too. This occured widely on flat beds. Within catchment areas there were only very small deposits of removed sand in front of the dams. In conclusion: Within the limits of a chosen risk, artificial microreliefs reduce completely erosion damages.  相似文献   

MicroLEIS: A microcomputer-based Mediterranean land evaluation information system   总被引：4，自引：0，他引：4  

D. De la  Rosa  J. A. Moreno  L. V. Garcia  J. Almorza 《Soil Use and Management》1992,8(2):89-96

Abstract. A computer-based land evaluation information system (MicroLEIS) was developed for optimal use of agricultural and forestry land systems under Mediterranean conditions. Through an interactive procedure several land capability, suitability and yield prediction methods may be applied. The system addresses land evaluation at reconnaissance, semi-detailed and detailed scales in an interrelated manner. Biophysical land evaluation methods are incorporated using empirical, scale-appropriate models, which range from purely qualitative (reconnaissance) through semi-quantitative (semi-detailed) to quantitative (detailed). This software is helpful for teaching, research and development, predicting appropriate agroforestry land uses. Its use is illustrated by an example.
MicroLEIS runs on IBM PC, XT, AT, or a compatible microcomputer with at least 128 kilobytes of RAM and a PC-DOS or MS-DOS version 2.0 or later operating system. The software package on double or high density diskettes can be obtained from the first author.  相似文献   

Differences in structure of organic matter in two soils as demonstrated by 13C cross polarisation nuclear magnetic resonance spectroscopy with magic angle spinning     

Michael A. Wilson  Peter F. Barron  Kuan M. Goh 《Geoderma》1981,26(4):323-327

Spectra of two whole soils have been recorded by cross polarisation n.m.r. spectroscopy with magic angle spinning. Magic angle spinning allows detailed structural comparisons between the types of organic carbon in whole soils to be made. Sufficient resolution is achieved to show that the two soils differ considerably in polysaccharide content.  相似文献