• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 50
  • 17
  • 17
  • 17
  • 17
  • 17
  • 17
  • 5
  • 3
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 83
  • 83
  • 12
  • 8
  • 8
  • 7
  • 7
  • 7
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • 5
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Studies on an eastern Ontario isolate of white clover mosaic virus

Khadhair, A. H. (A. Hameed) January 1983 (has links)
Characterization of the most frequently isolated virus found during a survey of eastern Ontario red clover fields, which was designated as the Ottawa isolate, was undertaken. Determination of the biological and physico-chemical properties of the virus showed that the virus studied differed in some respects from other WCMV isolates. An ultrastructural examination of virus localization of cytopathological changes in infected red clover and pea plants revealed various types of viral inclusions, including a membrane-bound mass of tubules, not usually associated with infection by potexviruses, in red clover leaves, and severe organelle disorganization within pea leaf tissues. WCMV infection significantly reduced several processes relevant to symbiotic nitrogen fixation, including plant growth, nodulation, nitrogenase activity, leghemoglobin content, and Rhizobium population, but nitrate reductase and acid phosphatase specific activities were increased. The correlation between leghemoglobin content and nitrogenase activity shown at ten-leaf and pre-blooming stages was absent during the flowering and senescence stages. Infectivity assays, immunosorbent electron microscopy, and an ultrastructural examination showed the presence of the virus in nodular tissues; the cytopathological changes seen in bacteroids suggested that virus infection accelerated nodule senescence. Application of a cytochemical technique using diaminobenzidine showed that the leghemoglobin was located in the peribacteroidal space.
62

ENHANCED EFFICIENCY NITROGEN FORMULATION EFFECT ON GRASS-LEGUME PASTURE PRODUCTIVITY

Payne, Kathryn Marie 01 January 2019 (has links)
The use of nitrogen (N) fertilizer is generally restricted on mixed species forage systems due to its stimulatory effect on grasses which increases competition with legume species. Reduced legume growth from this competition can compromise forage nutritive value and prospective yields. The controlled-release nature of several enhanced efficiency fertilizer N products holds the potential to improve legume persistence in mixed species pastures while providing supplemental N required by the grass component. The studies contained in this dissertation evaluated the effect of different enhanced efficiency N formulations (ATU, ESN, methylene urea, SuperU, and a 75% ESN: 25% urea blend) and untreated urea on yield, nutritive value, and legume persistence in a ‘Wrangler’ bermudagrass and ‘Durana’ white clover mixture (2014-2016 growing seasons), ‘KY-31’tall fescue and ‘Kenland’ red clover mixture (2015-2016 growing seasons), and ‘KY-31’ stockpiled tall fescue (2015-2017). The three studies were conducted at the University of Kentucky Spindletop Research Farm in Lexington, KY in a randomized complete block design. In the bermudagrass-white clover study, all enhanced efficiency N sources maintained white clover populations similar to the unfertilized grass/clover control, but only ESN caused greater clover composition than standard urea. Total forage yields increased linearly with N rate in all years, but dry weather conditions in the second and third years resulted in lower total yield. Forage nutritive value followed general trends throughout each growing season, but ESN’s ability to maintain clover resulted in higher nutritive value. In the tall fescue-red clover, total forage yields curvilinearly increased with N rate in 2015 but did not vary in 2016. ESN and ESN+urea blend treatments retained clover composition similar to that of the unfertilized control. Stockpiled forage yield increased with higher N rates. Enhanced efficiency N fertilizers with the ability to control N release can enhance forage yield while maintaining clover in mixed species swards.
63

Phytotoxicity and pathogenicity of Fusarium roseum against red clover

Blain, François, 1964- January 1988 (has links)
No description available.
64

Reclamation of a Midwest brownfield site using agronomic and turf species

Johnson, Amanda M. 14 December 2013 (has links)
Plant species were assessed for recolonization of a brownfield in Muncie, IN. In a greenhouse study, soil was seeded to perennial ryegrass (Lolium perenne), red clover (Trifolium pratense) and sunflower (Helianthus annuus). Selected pots were amended with leaf compost and mycorrhizal fungi. Soil and plant tissue were analyzed after 30 and 90 days. Ryegrass and compost were studied at the brownfield site. In the greenhouse, red clover was capable of concentrating the greatest quantity of Cd, Cu, Cr, Ni, and Pb in above-ground biomass (all soil treatments combined). Compost + mycorrhizal fungi treatment resulted in highest Cd, Cu, and Zn plant concentrations (all plant treatments combined). Compost resulted in the highest tissue Cr and Ni concentrations. The reported study demonstrates that this brownfield is capable of being revegetated by turf and legume species. Each infertile and/or toxic site must be assessed for revegetation species on a case-by-case basis. / Department of Natural Resources and Environmental Management
65

Antilipideminėmis savybėmis pasižyminčių vaistinių augalų veikliųjų medžiagų palyginamoji apžvalga ir raudonųjų dobilų (Trifolium pratense L.) žolės pritaikymo mažinti cholesterolio kiekį kraujyje pagrindimas / The comparative overview of antilipidemic active compounds from medicinal herbs and evaluation of red clover (Trifolium pretense L.) application for lowering cholesterol in blood

Bercevič, Renata 28 June 2011 (has links)
Darbo tikslas – apžvelgti Lietuvoje augančių antilipideminėmis savybėmis pasižyminčių augalų pritaikymo galimybes mažinti cholesterolio kiekį kraujyje bei pagrįsti raudonųjų dobilų terapinį potencialą. Tyrimo metodai. Bendrasis flavonoidų kiekis raudonųjų dobilų žolėje nustatytas UV spektrofotometrijos metodu. Raudonųjų dobilų veikliųjų medžiagų ADME savybių prognozė atlikta panaudojant ACD/ADME suite 5.0 programą. Statistinė analizė atlikta naudojant „Microsoft Office Excel 2003“ programą. Apskaičiuotas aritmetinis vidurkis ir standartinis nuokrypis. Tyrimo rezultatai. Daugiausia flavonoidų raudonųjų dobilų žaliavoje yra birželio mėn. pradžioje ir viduryje (0,46 ± 0,07 proc.). Liepos mėn. pradžioje flavonoidų kiekis sumažėja 2–3 kartus, o vasaros viduryje padidėja iki 0,33 ± 0,05 proc. Rugpjūčio mėnesį flavonoidų kiekis žaliavoje vėl sumažėja iki 0,29 ± 0,03 proc. Remiantis programos prognozėmis raudonųjų dobilų žolės veikliosios medžiagos pasižymi gana palankiomis ADME savybėmis, kurios leistų šio augalo preparatus vartoti per os. Dauguma veikliųjų junginių, ypač flavonoidų aglikonai ir kumarinai turėtų labai gerai absorbuotis pasyviosios absorbcijos būdu, o didžiausias bioprieinamumas per os (> 70 proc.) prognozuojamas biochaninui A, daidzeinui, formononetinui ir kumestroliui. Beveik visoms veikliosioms medžiagoms, kaip ir statinams, prognozuojamas nedidelis pasiskirstymo tūris: nuo 0,7 l/kg iki 1,6 kg/l. Visiems junginiams prognozuojamos labai mažos tikimybės, kad jie... [toliau žr. visą tekstą] / Objectives – to overview the possibility to use plants with antilipidemic properties growing in Lithuania to reduce cholesterol in blood and to substantiate therapeutic potential of the red clover. Methods. Total flavonoid amount in red clover was determined by using UV spectroscopy. ADME properties of red clover active substances were predicted by using ACD/ADME suite 5.0 software. Statistical analysis was carried out using “Microsoft Office Excel 2003” software. Arithmetical average and standard deviation were calculated. Results. The biggest amount of flavonoids in red clover raw material is detected in the beginning and middle of June (0.46 ± 0.07 %). The content of flavonoids decreases two-three times in the beginning of July, and increases to 0.33 ± 0.05 % in the middle of the summer. The flavonoid content of raw material decreases to 0.29 ± 0.03 % again in August. Based on program predictions the active substances present in the herb of red clover have beneficial ADME properties affording the preparations of this herb to use per os. Majority of active substances, especially flavonoid aglycones and coumarins should have very good absorption by passive route of absorption, and the highes oral bioavailability (>70 %) is predicted for biochanin A, daidzein, formononetin and coumestrol. Almost all active compounds, the same as statins, were predited to have low volume of distribution: from 0.7 l/kg to 1.6 l/kg. All compounds were prognosed not to be strong inhibitors of CYP... [to full text]
66

Genetic studies on resistance to alfalfa mosaic virus (AMV) and tolerance to white clover mosaic virus (WCMV) in red clover (Trifolium pratense L.)

Martin, Pierre. January 1989 (has links)
No description available.
67

Phytotoxicity and pathogenicity of Fusarium roseum against red clover

Blain, François, 1964- January 1988 (has links)
No description available.
68

Genetic studies on resistance to alfalfa mosaic virus (AMV) and tolerance to white clover mosaic virus (WCMV) in red clover (Trifolium pratense L.)

Martin, Pierre. January 1989 (has links)
No description available.
69

Boundary Dynamics Across Habitat Edges: Effects on Beneficial Insect Species Abundance and Richness

Whu, Alyssa 28 August 2012 (has links)
No description available.
70

Effect of several insects on the chemical composition of alfalfa, red clover, and birdsfoot trefoil

Mathur, Rishiraj Behari Lal January 1964 (has links)
To make use of the information on infestation estimates of forage insect pests obtained by the conventional methods of sampling, it is important to estimate the actual losses taking place in association with definite numbers of the insect. Six month old red clover, alfalfa, and birdsfoot trefoil plants were exposed for a month to spittlebug infestations of 0, 50, 100, and 150 adults. Although the spittlebug mortality was lowest when reared on alfalfa and highest on birdsfoot trefoil, yellowing appeared on alfalfa and birdsfoot trefoil. On red clover there was a consistent increase in protein and nitrogen free extract and a reduction in crude fiber and ash content indicating slight reduction in growth. None of these differences were significant. On alfalfa the loss of xylem sap due to feeding caused a consistent general reduction of proteins, fat and ash content and an increase in dry matter and nitrogen free extract. Of these constituents only the increase in dry matter was significant with an infestation of 150 spittlebugs per cage. No differences in dry matter, proteins and fat were significant. Another test on 4 month old alfalfa with infestation levels of 0, 100, 200 and 300 showed similar consistent patterns but the difference in dry matter was significant only when the infestation was 200 spittlebugs or more. On birdsfoot trefoil there was a consistent increase of dry matter, proteins, and ash and reduction of fat and crude fiber. Only the difference of dry matter and fats was consistent showing that an infestation of 100 or more spittlebugs per sq ft will affect the general growth of the plants. The survival of 1st instar nymphs of the pea aphid (a phloem feeder) was very poor on birdsfoot trefoil. There was a fair amount of survival on red clover and those on alfalfa survived fully. There was no visible symptoms on birdsfoot trefoil and red clover but the alfalfa showed retarded growth. On red clover there was a consistent increase of dry matter, fat, crude fiber and nitrogen free extract but a reduction of proteins. The difference in crude fiber was significant when the infestation was 1000 pea aphid nymphs or more. A consistent reduction of proteins and crude fiber was also recorded on alfalfa but these differences were not significant. On birdsfoot trefoil, there was a decrease in dry matter and an increase in fat and ash content. The difference in ash content was significant when the infestation of pea aphid nymphs was 1000 or more. Potato leafhopper (phloem feeder) injury was very characteristic on birdsfoot trefoil. The terminal 1 to 2 inches of the sterns became wilted and bent down. On alfalfa there was gradual yellowing and the retarded growth was evident. The red clover did not show any characteristic symptoms. Infestations of 20 or more caused a consistent increase in protein, fat, crude fiber and a reduction of nitrogen free extract. On alfalfa there was consistent decrease in dry matter. On birdsfoot trefoil, there was consistent increase in dry matter, fat, and nitrogen free extract but a reduction of crude fiber showing that feeding on birdsfoot trefoil probably retards growth and condensation of carbohydrates to form crude fibers. The increase in fat was significant when the infestation was 40 potato leafhoppers or more. Alfalfa weevil adult feeding caused characteristic stripping of leaves, girdling of stem and drying of the entire plant. Feeding of 10 or more weevils for 18 days on a two month growth of alfalfa after the 1st cutting, cause a consistent reduction of proteins, fat and crude fiber and an increase of dry matter, ash, and nitrogen free extract. Increase of percent dry matter was significant when the infestation of alfalfa weevil adults was 20 or more. In another test, the dry matter, fat and ash gave similar consistent results, when 40, 60, and 80 adults were fed on 4 month old alfalfa for 18 days. Reduction of percent fat was significant when the infestation was 40 or more alfalfa weevil adults. Alfalfa weevil larval feeding showed stripping of the leaves and buds. Infestation of 30 or less, 2nd to 4th instar larvae for 12 days caused a consistent reduction of fat and ash and an increase of dry matter, proteins and crude fiber. The infestation was not high enough to show a significant change in plant constituents. / Ph. D.

Page generated in 0.0423 seconds