To see the other types of publications on this topic, follow the link: Seed fund.
Dissertations / Theses on the topic 'Seed fund'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Seed fund.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Uusivuori, Mikael, Axel Andersson, and Latif Andersson. "Perceptions of Swedish Fund Managers of Equity Crowdfunding." Thesis, Internationella Handelshögskolan, Högskolan i Jönköping, IHH, Företagsekonomi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-26768.
Full textAbstract:
Equity crowdfunding (ECF) is the smallest of four main types of crowdfunding (CF) and has emerged as a new form of investment, where investors receive equity of a company in return for capital. Over the past years, the development of CF has given entrepreneurs the option to seek funding from a new source, instead of relying solely on venture capital (VC) and other sources of funding (Mollick, 2013). However, the implementation of regulations for ECF has not yet developed enough to make such investing equally consistent for everyone. Equity crowdfunded ventures can potentially attract a large number of investors that can possibly create corporate governance issues between the entrepreneur and investors. Additionally, individual investors might both lack the competence or incentive to extensively research and assess a venture and make an investment. Due to the growth in ECF and the lack of knowledge of it, the purpose of this thesis was to discover the perceptions of Swedish fund managers (FMs) regarding the nature of ECF and their interest in it. In order to fulfill the purpose of this study, previous studies were carefully examined to gain a thorough understanding of the area of study. Furthermore, the empirical findings were gathered through a course of seven semi-structured interviews of Swedish FMs. Empirical findings suggested that ECF has remained as a means of providing only seed-stage funding for ventures and that it is a marginal phenomenon in Sweden. ECF was believed to potentially disturb the VC industry if it grew and moved to a later stage. Additionally, ECF was found to be a good option for companies that were unable to receive funding from traditional funding methods. Risks of fraud and other scandals should be prevented for ECF to maintain its popularity. The findings implied that the future of ECF remains uncertain. Based on the perceptions of Swedish FMs, ECF neither would replace nor be a threat to traditional methods.
2
Štochlová, Karolina. "BUILDING ENVIRONMENT FOR INNOVATIVE START-UPS IN THE CZECH REPUBLIC." Master's thesis, Vysoká škola ekonomická v Praze, 2012. http://www.nusl.cz/ntk/nusl-125161.
Full textAbstract:
The goal of this thesis is to identify the challenges and success factors of the support system for innovative start-ups in the Czech Republic as well as to formulate recommendations for the implementation of the currently envisaged Seed fund project. The thesis covers the specifics of start-up companies and barriers for their development and puts them in relation with the current state of the Czech entrepreneurial environment and its innovation performance. Hard data as well as opinions of experts and potential investors are assessed to analyze the needs and motivations of both demand and supply sides of the venture capital market in order to provide some valuable insights which may help the support system to improve the access of entrepreneurs to external finance and boost the creation of innovative start-ups in the Czech Republic. The main suggestions introduced relate to the focus on retaining strict transparency, to the careful selection of entities evaluating the viability of projects and those providing services assisting the entrepreneurs in the preparation phase. Finally, the right setting of conditions of the Seed fund to attract both private investors and entrepreneurs will determine the success of the whole project.
3
Ejerhed, Johan. "Public-Private VC-funding : an oxymoron? Starting biotechnology ventures in Mecklenburg-Western Pomerania." Thesis, Linköping University, Department of Management and Economics, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2357.
Full textAbstract:
The purpose of this Master's Thesis is to investigate the outlooks for a seed stage venture capital fund investing in biotechnology-related spinouts from public research to be established in Mecklenburg-Western Pomerania, Germany. Recommendations on how to improve any discovered deficits of the fund's prerequisites are also to be presented.
Analyses showed that the spinout potential of the research in the region is weak. The entrepreneurial prerequisites of the researchers, in terms of previous experience, business knowledge and a track record that would vouch for them being suitable entrepreneurs, are generally poor. Nor is there sufficient industry in the region to facilitate the establishment of and subsequent businesses for the spinouts. The seed fund must therefore provide any future portfolio ventures with a substantial amount of Hands-on Management.
To improve the prerequisites for the seed fund, PVA-MV must influence the researchers'attitude towards spinouts and make the monetary gains more visible. The researchers must be imbued with a business approach in their research and PVA-MV must market its services as being the intermediary of government, universities and industry and as being able to create opportunities for researchers as well as for industry. PVA-MV should also focus on the few institutes and individual researchers that do have some favourable entrepreneurial characteristics, in order to evoke professional entrepreneurs with a forming track record. To cope with the deficient prerequisites of the fund, PVA-MV must expand the competence of its own work force and focus on the rate of return rather than on building regional infrastructure pro bono as a governmental agency.
4
Chang, Yu-Wei 1977. "Isolation and characterization of proteins from chickpea (Cicer arietinum L.) seeds." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=115839.
Full textAbstract:
Chickpea (Cicer arietinum L.) seed is a potential source of protein ingredients with desirable nutritional and functional properties. Knowledge of molecular characteristics of a food protein is essential before a protein can gain widespread use as a food ingredient. The objectives of this study were to prepare chickpea proteins using different extraction methods and precipitation methods and to investigate molecular characteristics using polyacrylamide gel electrophoresis (PAGE; Native and SDS), reversed phase high performance liquid chromatography (RP-HPLC) and electrospray ionization mass spectrometry (ESI-MS) techniques. Proteins of ground chickpea seed were extracted with sodium hydroxide (NaOH) and with citric acid solutions and precipitated with addition of acid and by cryoprecipitation. The protein contents of the protein preparation ranged from 49% to 97%. The microstructures of chickpea protein isolates examined by scanning electron microscope (SEM) revealed the presence of starch grains in the cryoprecipitates from citric acid extraction but not in isoelectric precipitates. The globulins (legumins and vicilins), glutelins, and albumins from both citric acid and NaOH isolates were characterized by Native-PAGE. The cryoprecipitates contained mainly the globulin-rich proteins. With SDS-PAGE characterization, protein subunits were identified as follows: (i) legumin subunits: MW 40, 39, 26, 23, and 22 kDa, (ii) vicilin subunits: MW 50, 37, 33, 19, and 15 kDa, (iii) glutelin subunits: 58, 55, and 54 kDa, and (iv) albumin subunits: 10 kDa. Separation of fractions of isolated chickpea proteins by RP-HPLC showed that early eluting fractions (Rt 20-30 min) consisted of subunits of MW 6.5-31 kDa (SDS-PAGE). At elution time 30-36 min, the fractions obtained were composed mainly of mixtures of legumin and vicilin subunits (MW 14-45 kDa). The major subunits of chickpea protein fractions from both cryoprecipitates and isoelectric precipitates are legumin basic subunit (MW∼23 kDa) and vicilin-rich proteins (MW∼19, 17, 15 kDa). ESI-MS analysis of fractions separated by RP-HPLC showed MW ranging between 5.1 and 53.5 kDa. The subunits of MW 35366, 27626, 22864, 20531, 16092, and 15626 Da of fractions from ESI-MS corresponded to MW 35.3, 28.0, 24.1, 20.5, 16.1, and 15.3 kDa identified in SDS-PAGE. These fractions were identified as legumin-rich and vicilin-rich proteins.
5
Koppitz, David. "Využití rizikového a rozvojového kapitálu pro podporu začínajících inovativních podniků v ČR." Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2012. http://www.nusl.cz/ntk/nusl-223659.
Full textAbstract:
Innovation entrepreneurship is built not only on a quality idea, but also on the availability of start-up capital and management skills of the idea owner. The insufficient finance often limits the success and growth potential of start-ups. When seeking support to individual business plans, allowing for entry of a business angel could be an option. Business angels are private, mostly experienced investors who invest in SMEs with high growth potential not only financial capital, but also business know-how, contacts and management experience. Thesis evaluates possibilities to use venture capital offered by business angels to support innovative start-ups and on several case studies assesses readiness of innovation and business environment from the investors’ point of view.
6
Kempe, Andreas, Christoph Neinhuis, and Thea Lautenschläger. "Adansonia digitata and Adansonia gregorii fruit shells serve as a protection against high temperatures experienced during wildfires." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-234853.
Full textAbstract:
The thick and woody shell of the fruit of Adansonia species cannot be explained solely by adaptation to zoochory or hydrochory. Since the trunks of Adansonia possess a thick and fire-resistant bark and wildfires occur regularly in its habitat (savannah), we examined with the African Adanonia digitata and the Australian Adansonia gregorii whether the fruit offers protection against high heat typically experienced in wildfires. Heat-resistance tests were conducted by applying a simple heat test based on known temperature and temperature residence times occurring in savannah fires and complemented by tests to reveal the impact of heat on germination since long-term seed dormancy is known for Adansonia. Germination tests with acid treated and heat treated seeds were performed to establish if heat also increased germination rate as effectively as acid treatments have been found to do. Heat was found to increase germination rate, but not as effectively as treatment with acid, therefore fruits exposed to high temperatures experienced in wildfires may have a better chance of germination than fruits that were not exposed to wildfires. The ability of the investigated fruits to protect seeds from high temperatures suggests that wildfires may have played a role in the evolution of the hard-shell structure typically found in Adansonia.
7
Asiedu, Ernest Assah. "The response of cowpea (Vigna unguiculata L. Walp) seeds differing in seed coat colour to storage and reduced water availability during germination." Thesis, University of Aberdeen, 1995. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU482662.
Full textAbstract:
These studies were conducted to determine the response of cowpea cultivars differing in seed coat colour to storage and reduced water availability during germination, and to relate these to the chemical composition of their seed coats. Seeds of five cowpea cultivars were stored under simulated tropical conditions (30°C/75.5% r.h.) for 6 months, subjected to accelerated ageing (40°C/100% r.h.) for 6 days or controlled deterioration (40°C/20% m.c.) for 4 days. Unpigmented seeds showed more rapid deterioration which was revealed by low germinations, high leachate conductivity and poor vital staining with 2, 3, 5 Triphenyl Tetrazolium Chloride (TTC). These differences were attributed to differences in moisture contents that occurred in storage as well as genotypic differences. Increased susceptibility to imbibition damage occurred during storage particularly in unpigmented seeds. The seed vigour parameters at the end of the stimulated tropical storage correlated well with accelerated ageing, suggesting the possible use of rapid ageing to predict the storage potential of cowpea seeds. Percentage radicle emergence was high in the pigmented cultivars germinated at -0.0015, -0.1 and -0.15 MPa and lower in unpigmented cultivars as matric potential was reduced. Imposition of reduced water availability (-0.15 Mpa) after 12, 24 and 48 hours germination at -0.0015 MPa led to slower rates of radicle emergence in all seeds transferred at 12 and 24 hours. In the unpigmented cultivars, these early transfers led to reduced radicle emergence after 7 days and low final normal germination after transfer to -0.0015 MPa for a further 7 days. This deleterious effect was revealed by poor vital staining of the embryonic axes. Protein synthesis of root tips after 24 hours -0.0015 MPa, 96 hours -0.15 MPa followed by a recovery period of 48 hours -0.0015 MPa was twice as much in the pigmented cultivar which explained its greater ability to recover from stress. Screening of a further ten cultivars for tolerance of reduced water availability revealed three groupings, (1) unpigmented cultivars that showed low final normal germination and rapid rates of water uptake in water, (2) smooth-coated pigmented cultivars that showed high final germination and slow rates of water uptake and (3) wrinkled -coated pigmented cultivars which showed intermediate germination and high rates of water uptake.
8
Jones, Naomi Elizabeth. "Temporal and spatial variation of the vegetation seed bank and seed-rain in set-aside and adjacent habitats." Thesis, University of Aberdeen, 1995. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU068101.
Full textAbstract:
In this study set-aside development was monitored (1989-1992) at Aldroughty Farm, Morayshire as part of an integrated project looking at plant and animal dynamics in set-aside, crop and semi-natural habitats. The vegetation, seed bank and seed rain were monitored in adjacent set-aside, semi natural and cropped areas. Initially set-aside vegetation consisted of annual arable species, but wind dispersed species and longer-lived perennials invaded rapidly. This process was more rapid on smaller plots and ingress of perennials occurred more quickly closer to the field margin. There was little invasion from adjacent semi-natural habitats and the field margin was the most important source of colonising species. Cropped areas were not significantly affected by adjacent set-aside. Seed banks were analysed using germination and extraction techniques which gave different estimates. Highest densities were found on set-aside land indicating the problems associated with returning set-aside to agricultural production. Changes in the seed bank were less apparent than in the vegetation, but within-year variation was great and carryover of seeds from October to March was low. The seed rain was monitored using gravel traps. Densities were highest on set-aside and lowest in the crop and wood. Individual species exhibited different phenologies in seed shedding, but peak deposition coincided with cutting. Dispersal from the set-aside into the crop was very low and dispersal distances were small. Vegetation and seed rain were similar in species composition in the set-aside areas. Although the seed rain was similar to seed bank samples taken immediately after seed shed, a large proportion of seeds did not enter the seed bank. Set-aside land did not develop into semi-natural habitat, however species diversity increased and the land provided a food source and an undisturbed habitat for animals. The real concern is the return of set-aside land to agricultural production, because of increased seed bank densities.
9
Kyereh, Boateng. "Seed phenology and germination of Ghanaian forest trees." Thesis, University of Aberdeen, 1994. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU068828.
Full textAbstract:
Seed production and germination of some timber tree species were studied in Ghana for possible prediction of seed yield and natural regeneration. Seed phenology in 13 species was monitored for two years, using permanent seed traps in two forest sites. Seed germination tests were conducted in neutral, green shade and dark in shade houses for 20 species. In the forest, germination was tested in forest gaps receiving different irradiances. Fruiting frequency ranged from twice in each year to supra-annual fruiting. Fruiting periods for species were consistent between years. Fruiting synchrony was higher among individuals of a population than between sites for the same species. Fecundity differed between years for the majority of species and between sites for species common to both sites. Premature fruit abscission was quite common. Maximum seed weight and percentage germination occurred during peak fall of mature seeds. Seeds of the majority of species germinated equally in light and dark and also in neutral and low red: far red ratio. These included some species previously classified as pioneers. In the forest germination was depressed in a large clearing for the majority of species. The use of photoblastic germination alone to define pioneers leads to a smaller group of pioneer species than is presently recognised. Large gaps due to logging may discourage natural regeneration.
10
Legesse, Nigussu. "Genotypic comparisons of imbibition in chickpea (Cicer arietinum L.) and cowpea (Vigna unguiculata (L.) Walp.)." Thesis, University of Aberdeen, 1991. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU546773.
Full textAbstract:
Examination of the imbibition characteristics of eighty chickpea genetic lines (53 Desi and 27 Kabuli types) and eleven cowpea cultivars revealed that in both species seeds with unpigmented testae imbibed more rapidly than the pigmented seeds. Rapid imbibition was associated with high solute leakage, indicative of possible imbibition damage. Further evidence of imbibition damage was revealed in cowpea where the rapidly imbibing unpigmented seeds had poor vital staining with tetrazolium chloride after 24h imbibition. In chickpea, all the genetic lines of white Kabuli seeds had similar rapid rates of imbibition. In contrast, the pigmented Desi genetic lines revealed a range of rates of water uptake although many imbibed more slowly than the Kabuli lines. The incidence of delayed imbibers, that is, seeds which failed to imbibe until after 8h in water, was the main reason for reduced rates of imbibition in Desi lines. The restriction to water uptake by the pigmented seeds was mainly influenced by the properties of the seed coat. In cowpea seeds, the permeability of the seed coat was the most important factor limiting water uptake whereas in chickpea the permeability of the seed coat as a whole and of the micropyle as well as the degree of adherence of the seed coat to the cotyledons were important in regulating the movement of water into the seed. Investigation of the rate of imbibition during the maturation of dwarf French bean, cowpea and chickpea seeds revealed that development of slow water uptake by coloured cultivars was clearly associated with the appearance of pigmentation. In chickpea, this also coincided with the development of the adherence of the seed coat to the cotyledons. In contrast, seeds from unpigmented cultivars imbibed rapidly at all stages of maturation. Examination of the seed coat anatomy of chickpea and cowpea indicated that the pigmented seeds tended to have shorter and narrower palisade cells and also shorter tracheid bars than the unpigmented seeds. Differences in water uptake by Kabuli and Desi seeds were not evident when seeds were stored at 100% relative humidity and 40oC for days. All seeds deteriorated at a similar rate. However, the importance of initial seed quality in influencing deterioration during storage was emphasised by the rapid loss of germination of the Kabuli seeds in which germination and vital staining revealed poor initial quality.
11
Daws, Matthew. "Mechanisms of plant species coexistence in a semi-deciduous tropical forest in Panama." Thesis, University of Aberdeen, 2002. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU160354.
Full textAbstract:
Niche-differentiation has been proposed to explain the coexistence of large numbers of tree species in tropical forests. Previous studies on established individuals have found little evidence for this. However, niche-differentiation may be apparent at the seed and seedling stages. This study investigated the effects of environmental variation in germination and seedling establishment for a range of Central Panamanian species. Firstly, topography has a large impact on soil water availability; slopes are wetter than nearby plateaux. The potential impact on seedling emergence and survival was studied by monitoring seedling emergence and survival over 15 months. This revealed that small-seeded species are unlikely to establish on plateaux, presumably because of the rider conditions. Secondly, the germination of four pioneer species in response to four environmental variables, related to canopy gap size, was investigated. Species exhibited consistent patterns of response suggesting adaptation for germination in particular gap sizes; Piper marginatum responded to nitrate, had a low base potential for germination and tolerated large temperature fluctuations, suggesting adaptation for germination in comparatively large gaps. Conversely, Pipe peltatum exhibited responses, which suggested adaptations for germination in small gaps. Finally, germination and seedling mortality for four pioneer species in two sizes of canopy gap was predicted using computer modelling. This indicated that large-seeded pioneers can germinate and establish in large gaps. Conversely, percentage germination and survival of small-seeded species was low in large gaps. However, small-seeded species produce greater quantities of seed than large-seeded species. Consequently they may "win by default" in large gaps, because of the absence of seeds of larger species. These results indicate that there are a number of axes of environmental variation along with nice-differentiation can occur. Furthermore, the response is variable between species. Thus niche-differentiation is important for fostering species coexistence, although density-dependent mortality and dispersal-limitation also contribute.
12
Thyagarajan, Palaniappan. "Evaluation and optimization of cranberry seed oil extraction methods." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110762.
Full textAbstract:
Cranberry seed oil is a fine quality oil which can be marketed for its many beneficial functions to human health due to the presence of a unique combination of omega- 3, 6 and 9 fatty acids and the high concentration of antioxidants. Although there is no available clear data about the oil percentage of cranberry seeds in literature, an experiment was done to analyze the oil yields obtained through different processes such as heat reflux, microwave and ultrasound, both quantitatively and qualitatively. During preliminary experiments, better oil yields were obtained with ground seeds (10.11 ± 0.2%) in comparison with unground seeds (8.17 ± 0.3%) , and hence the seeds were made into a fine powder using a blender and the fine powders were separated by sieve (1mm). Hexane (10.2 ± 0.2%) was also found to be more efficient in oil extraction than Hexane: Ethanol (7:3) (6.45 ± 0.1%). The oil extraction process was based on four major operating factors namely the sample/solvent ratio, temperature, time and applied power for the heat reflux, microwave and ultrasound extraction. The results showed that the oil yield increased with an increase in sample/solvent ratio at 10g/100ml of hexane, temperature of 70⁰C in heat reflux which provided an oil yield about 11.19 ± 0.1% while in the case of microwave, best conditions were for a sample/solvent ratio of 5g/30ml of hexane, power at 125W, which gave an oil yield of 24.15 ± 0.3% maintaining the temperature at 66⁰C. In comparison, with ultrasound extraction at a sample/ solvent ratio of 5g/30ml of hexane, and a power at 150W, the oil yield was 32.35 ± 0.3%. The best yield results obtained for the tested methods for extracting oil from seeds were found and compared as: Heat reflux < Microwave
13
Kelly, Robert Edwin. "'A lot more than the NGOs seem to think' the impact of non-governmental organizations on the Bretton Woods institutions /." Connect to this title online, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1110364714.
Full textAbstract:
Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xxi, 349 p.; also includes graphics (some col.). Includes bibliographical references (p. 324-349). Available online via OhioLINK's ETD Center.
14
Lowe, Robert 1961. "In vitro hardening, improved greenhouse minituber production and field performance of potato (Solanum tuberosum L.) cv. Norland." Thesis, McGill University, 1999. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21598.
Full textAbstract:
Micropropagated potato (Solanum tuberosum L.) plantlets are routinely used for producing specific pathogen tested minitubers in the Canadian seed tuber certification industry. In vitro hardening methods for micropropagated 'Norland' were investigated, involving full and half strength Murashige and Skoog (1962) based propagation medium supplemented with NaCl, KCl, CaCl2, polyethyleneglycol, or paclobutrazol. Ten different media treatments were compared for their effect on stomatal function and early transplant performance using porometry, microscopy, and direct ex vitro transplanting. PEG, NaCl and 1/2 MS + 3 mM Ca treatments did lead to decreased leaf water losses. However, these treatments did not improve ex vitro transplant performance compared to controls. Minituber production was investigated using ex vitro plantlets in a rockwool-based hydroponic system. Productivity was evaluated for treatments involving photoperiod pretreatment, planting orientation, planting density, and hilling. No difference in total yield was detected when plantlets were exposed to 12 compared with 16 hour photoperiod pretreatments. However, short photoperiod pretreatment increased the number of minitubers in the most desirable size range. Increased planting density reduced yield per plant. However, small increases in yield per m2 occurred with increased planting density. Hilling, pinching, and planting orientation had no effect upon minituber size, number, or overall fresh weight yield. Significant differences in minituber yield occurred in field experiments. Larger minitubers (10--40 g) had larger yields compared with smaller minitubers (1--5 g). These results will contribute to improved minituber production technology for the Canadian certified potato seed tuber industry.
15
Leclerc, Yves. "The production and utilization of potato microtubers." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41512.
Full textAbstract:
A protocol is presented for the rapid (28 days) induction of microtubers on micropropagated layered potato plantlets of 'Kennebec', 'Russet Burbank' and 'Superior' in medium devoid of growth regulators. With this method the addition of coumarin, 6-(2-chloroethyl)-trimethylammonium chloride and 6-benzylamino-purine to the microtuberization medium either had no effect or significantly reduced microtuber weight per plantlet. Increasing the incubation period from 28 to 56 days significantly increased the weight of microtubers per plantlet and the proportion of microtubers heavier than 1 gram. Increasing the volume of microtuberization medium from 50 to 100 ml significantly increased the number of microtubers per plantlet. Microtuber dormancy periods were cultivar-specific and microtubers $ le$250 mg had longer dormancy periods as compared to microtubers $>$250 mg. A positive correlation was established between endogenous abscisic acid levels and microtuber dormancy periods. Microtubers $ le$250 mg had lower specific gravity, fewer eyes and produce fewer sprouts than microtubers $>$250 mg. Microtuber-derived plants were generally single-stemmed. Severe physiological ageing treatment ($>$2500 degree-days) had no effect on microtuber sprout development, stem number, tuber number and only minimally influenced tuber weight of microtuber-derived plants. Decreasing field in-row planting density from 30 to 10 cm reduced tuber weights and numbers per plant but increased them on a per hectare basis. Economic analysis indicated that optimum planting density varied depending on plantlet cost. The optimum planting density was 10 cm if the cost of the plantlet was $0.10 or less, 20 if plantlet cost were from $0.10 and $0.20 and 30 cm for plantlet cost greater than $0.20. A potato seed tuber certification program adapted to the needs and constraints of Egypt is presented.
16
Schafhauser, James. "Reverse genetics of mucilage synthesis in the Arabidopsis thaliana seed coat." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=112361.
Full textAbstract:
In Arabidopsis, the mucilage secretory cells (MSC) of the seed coat produce a pectinaceous mucilage. Very little is known about which genes are involved in the synthesis of pectins. A reverse genetic approach was used to identify genes involved in mucilage synthesis. A publicly available microarray database was screened with expression visualization tools, and was complemented by in-lab microarray experiments between wild type and known MSC mutants to identify candidate cell wall genes highly expressed at the time of mucilage synthesis. Several cell wall genes were also chosen based on their putative functions which would implicate them in mucilage synthesis. Phenotyping of mutant lines obtained for the cell wall candidate genes revealed no abnormal mucilage phentoypes in single or select double mutant lines. These results indicate that significant genetic redundancy exists in cell wall genes and/or the genes studied do not play significant roles in mucilage synthesis.
17
Thornton, Janet M. "The assessment and improvement of seed quality in Brassica oleracea L." Thesis, University of Aberdeen, 1990. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU031813.
Full textAbstract:
A survey of the quality of brassica seed used for commercial transplant production revealed that overall germination was high but that there was a wide range of seed vigour, as assessed by the controlled deterioration test. These vigour differences were reflected in the performance of seed in modules, the use of low quality seed resulting in problems of a reduced rate of emergence and a lack of seedling uniformity. The improvement of seed quality was considered using three approaches. First, the use of seed soakwater conductivity as a means of predicting germination was investigated for individual seeds. This proved not to be a reliable means of sorting seeds. However, the combination of controlled deterioration followed by assessment of conductivity on bulks of seeds gave a good indication of vigour and was developed as a possible rapid vigour test. Secondly, the relation between seed size and seed performance was examined. No clear relationship was found between seed size and seed quality, although, seed size had a marked effect on seedling growth, the larger seeds consistently producing taller seedlings. Thirdly, a physiological means of seed improvement was considered. Aerated hydration in water columns was successful as an invigoration treatment resulting in increased germination rate, root length of seedlings and seed vigour leading to enhanced performance in modules. These improvements were maintained after drying and storage. The optimum short-term treatment was 8 hours hydration at 25oC. The improvement could be partly attributed to germination advancement and in addition the effect of temperature, aeration and the greater improvement of aged seeds suggested that repair processes were activated during aerated hydration. Also, prolonged hydration for up to 32 hours gave an improvement such that the performance of aged seed was not significantly different to unaged seed. Finally, one possible mechanism by which aerated hydration resulted in such improvements in seed quality was investigated. DNA synthesis began approximately 24 hours earlier in unaged than in aged seed. Hydration reduced this lag phase, indicating that the onset of DNA replication was accelerated. The use of hydroxyurea, an inhibitor of DNA replication, indicated that the repair of accumulated DNA damage may have been occurring between the 16th and 32nd hours of germination.
18
Kasumu, Exildah Chibengele Chisha. "Improving exploitation of Pterocarpus angolensis : seed germination, micropropagation and genetic diversity." Thesis, University of Aberdeen, 2005. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU207620.
Full textAbstract:
Studies of seed dormancy breakage, micropropagation and genetic diversity were conducted on seed from Zambia and Zimbabwe. In seed dormancy breakage, nicking part of the seed coat and gibberellic acid treatments GA3 and GA4/7 were investigated. In Study 1) nicking had significantly higher germination, with a rate of 99% within five days of sowing, whereas GA3 treatment and the control had 65 and 69% germination respectively after four weeks. In study 2) 36, 36, 55 and > 91% germination were obtained with GA4/7, GA3, the control and nicking respectively after six weeks. In micropropagation experiments designed to investigate the optimum conditions for plantlet production, 6-benzylaminopurine (BAP), isopentenyl-adenine (2-iP) and thidiazuron (TDZ) were tested for shoot induction of cuttings from four weeks old P. angolensis seedlings. BAP at 5 mg.l-1 had significantly higher shoot multiplication compared to 0 - 2 mg.l-1 BAP concentrations. Sprouted axillary buds in 0.1 to 2 mg.l-1 TDZ treated cuttings did not elongate to usable sizes compared with BAP treated shoots. 2-iP at 0.5 - 5 mg.l-1 produced roots instead of shoots. Indole-3-butyric acid (IBA), indole-3-acetic acid (IAA) and the control were tested for ability to root cuttings. IAA at 1 mg.l-1 and IBA at 1- 4 mg.1-1 had a significantly higher number of roots. The control was efficient in root production. Using RAPD markers, within population genetic variation was revealed. Moderately high population differentiation of PHIst = 0.165 and 0.192 were found in two studies. This revealed significant gene flow between populations. These studies can be used to guide sustainable management, utilisation and domestication of P. angolensis in the future.
19
Di, Lollo Antonio B. "Thermal and surface properties of crystalline and non-crystalline legume seed proteins." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59973.
Full textAbstract:
This work was devoted to the study of (a) the physico-chemical, functional, and structural properties of bean (Phaseolus sp.) protein isolates in relation to their microstructures, and (b) the effects of protein carbohydrate interactions on physico-chemical, functional, and structural properties. The contents of protein, and both total and individual sugars of alkali extracted (amorphous) and citric acid extracted (bipyramidal and spheroidal) proteins from Phaseolus vulgaris (white kidney and navy) and Phaseolus lutanus (baby lima and large lima) beans were determined. The proteins were subjected to differential scanning calorimetry, and measurements of surface tension (air-water interface), surface hydrophobicity, and foam expansion. Structural analysis of the proteins were performed using Fourier transform infrared (FT-IR) spectroscopy. Enzymatic and chemical deglycosylation was performed on a white kidney bean protein isolate.Glucose and mannose were the major sugars found in the isolates. Bipyramidal and spheroidal microstructures with higher protein contents generally had greater mannose content and lower glucose content. Differences in enthalpy of denaturation $( Delta$H), surface tension decay curves, surface hydrophobicities, and foam expansions were observed with isolates of different microstructures. Corresponding differences in molecular structure were not, however, detected by FT-IR spectroscopy. Using statistical analysis, a relationship between foam expansion and the $ Delta$H, solubility, surface hydrophobicity and surface tension of the isolates was obtained. Preliminary results suggest that the removal of carbohydrate influenced the physico-chemical properties of the protein.
20
O'Donoughue, Louise (Louise S. ). "A study of seed dehiscence in the genus Lotus (Fabaceae) using interspecific hybridization and embryo culture /." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65420.
Full text
21
Sinclair, John. "Crusting, soil strength and seedling emergence in Botswana." Thesis, University of Aberdeen, 1985. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU363198.
Full textAbstract:
This thesis gives the results of an investigation of the strengths and particularly the crust forming potential of arable soils from Botswana and the relationship to seedling emergence of sorghum, the most important crop in Botswana and one that because of its small seed weight (about 2 0 mg) can fail to emerge through a hard soil crust. A review of the literature suggested that the soil factors which had to be considered were dispersibility of clay and factors which affect this, and the bulk density of the soils. Soils which are found in many tropical and sub-tropical regions, with low organic matter and inactive clays can set hard after a simple wetting and drying cycle. In these soils, the strength is very strongly dependent on the water content, showing a hyperbolic or exponential relationship-, and the strengths when dry may be very greatly increased by remoulding the wet soil. The crust strength required to prevent seedling emergence varies with the size of the seedling and for cotton (seed weight about 80 mg), 1-3 MPa penetration resistance measured with a penetrometer is sufficient to prevent emergence. Seedlings exert a total force proportional to their number. In the experimental programme, seedlings' forces were measured, seedling emergence observed in a field experiment under crusting conditions, and the strength characteristics of a group of soils, representative of arable soils in Botswana, studied. A sorghum seedling was found to exert a maximum force of about 1 N or dividing by the area of the plumule, a pressure of about 0,5 MPa. The field experiment showed that much better emergence was obtained from planting 15 seeds together than from planting 4 seeds together when a crust formed after planting. A study of 32 soils, most of them sand to sandy loam in texture but with a few clays and hydroirorphic soils, from arable areas in Botswana showed the sandy to sandy loam soils to have high bulk densities ( 1,45-1 ,75 Mg/m3) and extremely low organic carbon contents (0,12-0,85 g/100g). The bulk densities of all the soils were inversely related to the organic carbon content and this was itself related to the clay content of the soils. The bulk densities of the sands were dependent on the grading of the sand fraction. Many of the soils were sensitive to remoulding in the Emerson test and the sands to loany sands had 0,4-1,0 g/100 g water dispersible clay. Measurements of tensile strength on air-dry samples showed that all the soils, except for one sand, set hard after a wetting and drying cycle, giving for vacuum wet samples indirect tensile strengths 1,0-14,4 kPa. For the sands to sandy loams this strength was related to the water dispersible clay content. Samples wet at atmospheric pressure were weaker than the vacuum wet samples, the reduction in strength was related to the air porosity of the non-vacuum wet soils prior to drying. Remoulding the soils prior to drying them increased the strength by a factor of up to 50 times, giving strengths from 4 kPa to 600 kPa. The strength after remoulding was dependent on the Emerson index. Compacting the soils increased their strength greatly and to an extent that agreed with the hypothesis that the strength obtained was proportional to the area of contact between the particles. Experiments on penetration resistance at a range of water contents were performed on a few soils. A hyperbolic relationship between water content and penetration resistance of the surface soil was found for sand to sandy loam soils, with the maximum resistance of dry soils above 2 MPa. The penetration resistance of the sandy loam soil was Increased three times by disturbing it when wet. Sprinkler wetting the sieved soils was not found to affect the penetration resistance by a large amount compared and other methods of welting. Penetration resistance was measured on air-dry samples of most of the main group of soils following varying degrees of wetting with a rainfall simulator. The clays and hydromorphic soils gave very low values of penetration resistance under these conditions, showing that at organic carbon contents of about 1% and clay contents from 20 to 30%, the decreased bulk density and tendency to form aggregates' on drying overcame the tendency to set hard. The mean values for the sands to sandy loams were from 1 to 6 MPa so all these soils could offer significant resistance to a sorghum seedling. The penetration resistance of the sands and loam/ sands depended on their bulk densities and water dispersible clay contents, while the penetration resistance of the sandy loams depended only on the water dispersible clay content.
22
Ferguson, Andrew J. "The agronomic significance of seed quality in combining peas (Pisum sativum L.)." Thesis, University of Aberdeen, 1993. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU554221.
Full textAbstract:
Field emergence trials in NE Scotland of 29 commercial seed lots (80&'37 germination) from five cultivars of combining pea (Consort, Countess, Progreta, Bohatyr and Orb) in 1989, and of 26 of these lots in 1991, revealed large differences in field emergence indicative of differences in vigour. Laboratory germination (NG) was poorly related to the field emergence potential (FEP) of lots. The tetrzolium staining (TZ) test, mean time to germination and probit theoretical initial germination (K_i) were the best overall predictors of FEP. Seed leachate tests (electrical conductivity and N content) gave a good indication of the FEP of lots within individual cultivars but, because of the inherently lower solute leakage from lots of cv. Progreta, correlations for all cultivars together were poor. The influence of sowing date and harvest date on seed quality in combining peas was investigated in a study over two years (1990 and 1991). Only when the date of sowing was very late (mid-May) did it have any measurable deleterious effect on seed quality. Time of harvest had, in contrast a highly significant effect on seed quality; premature harvesting produced seed of poor quality, and although delays in harvest beyond the stage of maximum seed quality had little effect on the viability and vigour of cleaned seed, the yield of such seed was severely reduced. The ability to germinate normally after drying was maximal in seeds harvested at the end of seed-fill (seed moisture content &'61 56&'37) in both seasons. Maximum seed vigour, as assessed by leachate conductivity, TZ, controlled deterioration, K_i and field emergence tests, was, however, in the 1991 trial, reached much later at between 11 and 18 days after the end of seed-fill (smc &'61 23-36&'37). Finally, experiments on plants grown under conditions of minimal competition showed no effect on seed vigour on plant growth and yield that could not be explained by differences in the rate of germination and emergence.
23
Rwehumbiza, Filbert. "The effect of seed and soil physical conditions on establishment of sorghum." Thesis, University of Aberdeen, 1994. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU538899.
Full textAbstract:
The studies reported here, used sorghum to: (i) investigate the effect of changes in the matric suction (m) of filter-paper on germination and water uptake (ii) assess the effect of seed vigour on seedling response to the m of filter paper and to soil mechanical impedance, (iii) investigate the effect of root-shoot interaction on establishment of seedlings subjected to mechanical impedance (MI), and (iv) evaluate the effects of different amounts of planting rain on crop establishment. A technique for controlling matric suction on seed test paper is described and used to study seed germination at m of 0.1, 1 and 10 kPa. Time to 50% germination was increased, and final lengths of both radicles and cleoptiles reduced by an increase in m from either 0.1 to 1, or 1 to 10 kPa. A link between filter paper m, seed-liquid contact area, seed size, the rate of water uptake and germination is discussed. Unimpeded, pregerminated low vigour and fresh seeds produced a similar root and shoot length, fresh mass, and number of leaves and lateral roots. When grown in compacted soil, low vigour seed took longer to emerge but only when seeds were severely aged. (i) Impedance to the shoot delayed emergence, more so when the root was also impeded. (ii) Shoots emerging through a mechanically impeding layer, had greater extension rates after emergence than unimpeded ones. (iii) Mesocotyls became thicker only when the root systems were impeded. (iv) Impeding the shoot system, increased root extension rate. (v) The length of the first internode, the number of leaves and the spacing of lateral roots were not changed by any of the treatments. Germination was >95% in sand columns watered with 5, 10 or 15 mm equivalents of rain. However, seedling emergence was <15% in the 5 mm compared to 77-100% in the 10 and 15 mm treatments. At harvest (9 DAP), all seedlings in the 5 mm treatment were dead. Seedlings given 10 mm rain showed signs of water stress. The interaction between seed vigour, the amount of water available to germinating seed, and soil mechanical impedance and their effect on crop establishment is discussed.
24
Sipos, Gabriella. "The mechanisms of action of Sodium oxalate seed stabiliser molecules under Bayer conditions /." Curtin University of Technology, School of Applied Chemistry, 2001. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=12616.
Full textAbstract:
Sodium oxalate is one of the many organics present in Bayer liquor. Due to its limited solubility, sodium oxalate can co-precipitate with alumina trihydrate during precipitation. This can have detrimental effects on the final product quality, especially if it occurs in the initial stages of precipitation.Quaternary amine type cationic surfactants can prevent sodium oxalate co-precipitation and increase the tolerable concentration of sodium oxalate in Bayer liquor. Their action is via the inhibition of nucleation or/and the inhibition of crystal growth. This study presents work detailing the effect of quaternary amines on sodium oxalate crystal growth in Bayer liquor.A series of quaternary amines were tested and classified as strong, medium or weak crystal growth inhibitors in plant liquor. The octadecyltrimethylammonium bromide was found to be the most effective under plant conditions.Results will show that while quaternary amines inhibit crystal growth in Bayer liquor, they have no effect on crystallization in synthetic liquor. It has been postulated that the presence of certain organic molecules is required for quaternary amines to crystallization and therefore stabilize the liquor. The inhibition of oxalate crystal growth in Bayer process liquors is due to the plant organics present, and the stabilizing effect of quaternary amines is the result of an interaction between quaternary amines and plant humic material on the oxalate surface. A series of organics, anionic macromolecules and anionic surfactants, have been tested to simulate the behaviour of plant humates, and their inhibitory effect on sodium oxalate crystal growth has been measured.A method for the analysis of the strongest quaternary amine has been adopted, improved and modified in order to fulfil experimental conditions.The CMC of quaternary amines has been determined in liquor. Surface tension ++measurements revealed relationships between certain liquor components and quaternary amines.Adsorption isotherms of quaternary amines have been successfully generated in Bayer liquor. Investigations with quaternary amines and plant humics reveal a synergy between the two. Co-adsorption of quaternary amines and plant humates onto the oxalate surface has been found, and the effect of the components on the adsorption behaviour will be discussed. The inhibitory effect and the adsorbed amount of components have been compared. Results revealed a relationship between the amount of plant humates on the surface and the crystal growth inhibition.The nature of the adsorption has been investigated with confocal laser scanning microscopy. These results will show that humic material adsorbs at the edges and in the corners of the crystals. In the presence of quaternary amines, the humic material occupies the main crystal faces as well. The nucleation of sodium oxalate from humic solution and from a mixture of humates and quaternary amine resulted in crystals with different morphology.Fourier Transform Infrared Attenuated Total Reflection Spectroscopy investigations will present the adsorption of quaternary amine on oxalate, and will indicate that the adsorption is pH dependent.
25
Abusriwil, Abir. "Development of a nasal drug delivery system using Capsella bursa-pastoris seed mucilage." Thesis, University of Strathclyde, 2016. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=27401.
Full textAbstract:
Myxospermous seeds are characterised by the secretion of mucilage around the seed during germination. Capsella bursa-pastoris is an annual or perennial herbal plant of Brassicaceae family which has myxospermous seeds. This thesis studied extracted Capsella bursa-pastoris mucilage to see if it could be employed as a drug delivery system targeting the nasal cavity. Firstly, different extraction methods were used to extract the mucilage from Shepherd’s purse seeds without other contaminating components present from the seed coat. The extraction methods included the use of different solvents and temperatures. The extracts were freeze dried and underwent extensive studies of their physical (moisture content, glass transition temperature) and chemical (degree of esterification, carbohydrate composition) characteristics to compare them. Physicochemical properties of mucilage were studied using different approaches to understand the mucilage behaviour and assess its ability to be developed into a drug delivery system. The colorimetric identification of mucilage components, found rhamnose and uronic acid, which was indicative of extraction of a pectic type polymer. Fourier Transform Infra-Red (FTIR) examination of the different samples of mucilage suggested that the polymer was a polygalacuturonic acid. These findings were supported by Nuclear Magnetic Resonance (NMR) findings of an uronolactone structure which was predicated from intramolecular esterification of the uronic acid to form a lactone ring. The vapour sorption ability of mucilage was measured by DVS and was found to be huge and capable of adsorbing 50-70% of its weight accompanied with crystallisation at temperature below room temperature (17°C) and relative humidity as low as 10% assessed by Differential Scanning Calorimetry (DSC). Mucilage was thermally unstable and lost its adsorbed moisture at 40°C when it was heated in Thermo-Gravimetric Analysis (TGA). The different solvent extractions produced extracts with similar characteristics. All extracts were further examined for their mucoadhesion characteristics using Atomic Force (AFM) spectroscopy. An AFM study of the mucoadhesion of the mucilage to mucin coated mica sheets showed that the mucoadhesion power of extracted mucilage to mucin was higher than that of standard pectin and hydroxylpropylmethyl celluloses K100 which are widely used for drug delivery. It seemed that the mucilage would be a good candidate for a drug delivery system to the nasal cavity due to its mucoadhesive property. After assessing the physicochemical properties of all mucilage extracts and their mucoadhesion ability, water maceration extract was chosen for the development of the drug delivery system. Paracetamol and amitriptyline were chosen for their solubility properties as drug models. Different dosage forms with different surface areas were formed using the mucilage and the chosen drugs. Drug release properties from the different forms (discs and inserts) were assessed using Franz cells of diffusion. Shepherd’s purse mucilage was successfully formed into a drug delivery form able to deliver drugs to the site of administration by the effect of a plasticiser. Additionally, the mucilage drug delivery system was able to take up and release drugs. However, % paracetamol released from the mucilage inserts was not different from the % released from HPMC K100. The calculated similarity factor of the release profile of amitriptyline from mucilage and HPMC K100 nasal inserts was 43.5. Furthermore, the similarity factor of amitriptyline release from nasal discs of mucilage and HPMC K100 was 59.6. The drug delivery system from mucilage was as effective as HPMC K100 in drug release profile. The developed drug delivery system was able to adhere to mucin stronger than HPMC K100 and commercial available standard pectin; however, the pseudoplastic behaviour of the mucilage used to develop the system would lead to reduction of the viscosity of the system upon application. It is expected that as a result the drug delivery system could be washed out of the nasal cavity before delivering its drug content. Further drug delivery studies are required using ex vivo and in vivo methods to assess its suitability for developing a new drug delivery system. Nevertheless, the results presented in this thesis show that the mucilage could be a viable nasal drug delivery system and worthy of further investigation.
26
Lambert, Frank R. "Fig-eating and seed dispersal by birds in a Malaysian lowland rain forest." Thesis, University of Aberdeen, 1987. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU010096.
Full textAbstract:
This study investigates avian fig-eating and Ficus seed dispersal in a patch of lowland rainforest at Kuala Lompat, Peninsular Malaysia, in the period March 1984 to April 1987.Of 38 Ficus species identified in c.2 km2 of forest, 29 possessed seeds primarily dispersed by birds. A phenological study of these species showed that figs were available in every month, and that the Ficus community exhibited distinct aseasonal fruiting rhythms. Nevertheless, crops of large figs (>25mm mean dimension) were rare, with only 13--16 large-fruited fig-patches per km2 of forest per year. The 60 bird species which ate figs at Kaula Lompat partitioned the fig resource according to fruit size, even though the soft nature of figs enabled birds of all sizes to feed on figs of all sizes. All birds, except some pigeons, rapidly defaecated ingested Ficus seeds. Treron pigeons were specialised fig-seed predators, and were found to eat large proportions of some fig crops; c.30% in one studied fruiting. Radiotracking and observations of foraging birds showed that many species stayed close to large fruit patches. As a consequence of this behaviour, and rapid gut-passage rates for Ficus seeds, seed shadows of bird-dispersed Ficus are anticipated to be leptokurtic. The most important Ficus seed dispersal agents, in terms of long distance dispersal, are predicted to be the larger, specialised frugivorous birds. Bird-dispersed Ficus at Kuala Lompat were all epiphytic species, growing predominantly on large commercial timber trees. Selective logging of lowland forest is therefore predicted to severely deplete the density of bird-dispersed Ficus, especially those species with large figs. Birds particularly dependent on such figs, such as Treron capellei and some of the hornbills, are severely threatened by such practices. Recommendations are made to promote the survival of these vulnerable bird species.
27
Khalyfa, Abdelnaby. "Isolation, purification and characterization of lipoxygenase isozymes from canola (Brassica napus cv, Westar) seed." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59272.
Full textAbstract:
Lipoxygenase was extracted from Canola seeds (Brassica napus cv, Westar) and partially purified by precipitated with ammonium sulfate at 20-50% of saturation. The optimum pH for the enzyme activity was 7.5 and its K$ sb{ rm m}$ value was 2.0 $ times$ 10$ sp{-4}$ M. The activity of the enzyme extract was considerably greater on linoleic acid than on its ester or on linolenic acid. The effect of cyanide on the enzyme activity was also investigated.Further purification of the enzyme extract was performed by successive chromatography on ion-exchange and gel filtration, using FPLC system. Four lipoxygenase isozymes (I, IIA, IIB and III) were separated. The homogeneity of each isozyme was demonstrated by the presence of a single protein band on SDS-PAGE gel electophoresis. The molecular weights of isozymes I, IIA, IIB and III were, respectively, 72,000, 106,000, 78,000 and 62,000. The optimum pH for lipoxygenase activity was 6.5 for isozyme I and 6.0 for isozymes IIA, IIB and III.
28
Archibald, Devan. "The influence of reproductive timing on white spruce seed escape and red squirrel hoardin." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104881.
Full textAbstract:
This thesis evaluates how reproductive timing influences red squirrel hoarding of white spruce cones, from the perspective of both the trees and the squirrels. This was accomplished for white spruce by assessing the degree of intra-annual reproductive synchrony exhibited by individual trees relative to others in the population and the amount of cones (i.e. seeds) escaping red squirrel predation. In two years with vastly different cone production at the population level, individual white spruce trees exhibiting higher levels of intra-annual reproductive synchrony had enhanced seed escape from red squirrels, leading to positive directional selection on this trait in the lower cone year. In red squirrels, we used behavioural observations of radio-collared individuals to assess how variation in the temporal separation of breeding and hoarding seasons, across four-years of varying cone production, affects cone hoarding behaviour. Hoarding behaviour was more affected by cone levels than reproductive timing and under high cone levels both activities were successfully combined. However, males and females used different hoarding strategies that were consistent with differences in the timing of reproductive demands, indicating that although overall hoarding behaviour was driven by resource levels, the timing of reproduction may be a factor in gender differences. The seasonal scheduling of reproduction in white spruce trees appears to be an important component of seed escape from red squirrels, and although the timing of reproduction may promote gender differences in hoarding behaviour of red squirrels, it is less important than cone production to overall hoarding behaviour, allowing red squirrels flexibility in their reproductive timing relative to hoarding.Cette thèse évalue comment la phénologie reproductive influence la collecte de cône d'épinette blanche par l'écureuil roux, de la perspective de l'arbre et de l'écureuil. Chez l'épinette blanche, nous avons évalué le degré de synchronie reproductive intra-annuelle de chaque arbre relatif à la population et le nombre de cône (graines) qui échappe à la collecte des écureuils roux. Pour deux années avec des productions de cône très différentes au niveau populationnel, les épinettes blanches davantage synchronisées intra-annuellement dans leur phénologie reproductive ont davantage de graines qui échappent aux écureuils, menant vers une sélection directionnelle positive sur ce trait lors d'une année de faible production de cône. Chez l'écureuil roux, au cours de quatre années avec des productions de cône très différentes, nous avons utilisé des observations comportementales pour évaluer comment la variation dans la séparation temporelle entre les saisons de reproduction et de la collecte affecte le comportement de collecte. L'activité de collecte de cône est affectée davantage par le niveau de production annuelle de cône que par la phénologie de reproduction de l'écureuil et, avec un haut niveau de production de cône, les deux activités peuvent être combinées avec succès. Cependant, les males et les femelles utilisent des stratégies différentes selon leur différente phénologie de demande reproductive, indiquant que malgré que le niveau de ressource soit déterminant sur l'activité de collecte, la phénologie de reproduction pourrait être un facteur dans la différence entre les sexes. La phénologie de reproduction de l'épinette blanche semble être une composante importante de la survie des graines face aux écureuils roux, et malgré que la phénologie de reproduction puisse promouvoir une différence dans l'activité de collecte entre les sexes, cela est moins important que la production de cône pour l'ensemble de l'activité de collecte, ce qui permet à l'écureuil roux d'être flexible dans sa phénologie reproductive par rapport à la collecte de cône.
29
Liu, Yandi. "A study of the biochemical development and toxicology of the seed of Santalum spicatum." Curtin University of Technology, School of Pharmacy, 1997. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=12031.
Full textAbstract:
The seed of Santalum spicatum is rich in a fixed oil (59% by weight), which is characterised by a high percentage of acetylenic, ethylenic ximenynic acid (35% of total fatty acids). A number of important aspects of the seed fixed oil, its composition in developing seeds, its triacylglycerols molecular species in the oil, the nutrition and toxicity of the oil feeding, and the possible bioactivity of ximenynic acid in mice were investigated.The identification of cis and trans isomers of ximenynic acid in the seed oil, and the metabolite of ximenynic acid in mouse liver lipid fractions were achieved using 2-amino-2-methyl-1-propanol to form 2-substituted 4,4-dimethyloxazoline derivatives, which were analysed by gas chromatography with mass spectrometric detection.Changes in proximate and fatty acid composition were investigated in developing seed collected weekly from about seven days after flowering to maturity. It was determined that moisture and carbohydrate contents decreased significantly during the development sequence, while fixed oil content increased from 0.3% to 50% (by weight) with seed development. A corresponding increase in the proportions of both oleic and ximenynic acids occurred suggesting a precursor/product relationship. Mature seed collected from different locations in Western Australia showed minor differences in characteristics and lipid composition, which may have been influenced by geographical origin and harvesting year of samples.The lipid components from the seed oil were separated using thin-layer chromatography and the individual triglyceride bands were characterised by high performance liquid chromatography and gas chromatography using flame ionisation and mass spectrometric detection after removal from the plate. The triximenynin (trisantalbin) band showed no other contaminating fatty acids and was obtained in a relatively pure state.A ++nutrition and toxicity study was performed by feeding a semi-synthetic diet containing sandalwood seed oil to a level of 15% of total energy content to a group of mice for one month and another group for two months. The most significant effect of sandalwood seed oil ingestion when compared with a standard lab diet (5% fat, by weight) and a canola oil-enriched diet (15% fat, by weight) was an apparent reduction in body weight gain, which may be the effect of ximenynic acid as a growth retardant. Serum aspartate aminotransferase levels were determined in the mice as an indicator of hepatotoxicity. These levels were higher in mice fed the sandalwood seed oil diet than those fed the standard lab diet, suggesting that ximenynic acid may affect liver-specific enzyme activity. Analysis of the total lipid fatty acids of various tissues and organs of mice showed only a low incorporation of ximenynic acid into the general tissues (0.3-3% by weight), and its absence in the brain.This study suggests a few health benefits from consumption of large quantities of sandalwood seed oil in the diet. These include a low lipid content in blood, heart, muscle, increase in the 16:1/16:0 and 18:1/18:0 ratios, production of increased levels of 18:1 (n-9) and docosahexaenoic acid, and decreased levels of arachidonic acid in certain tissues. There were no specific pathological, morphological or mortality changes observed in the mice.Sandalwood seed may be both a food and a medicine.
30
Bastiani, Celia. "Seed coating with Fusarium oxysporum M12-4A for the biocontrol of Striga hermonthica Del. Benth." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32755.
Full textAbstract:
Fusarium oxysporum M12-4A fungus is being evaluated for the biocontrol of Striga hermonthica, a parasitic weed of African cereal crops. The production of M12-4A inoculum was assessed in four Malian villages using local technology and substrates. A delivery system using arabic gum to temporarily glue inoculum powder onto the crop seed was tested. In controlled conditions, coating of sorghum seeds with arabic gum and inoculum powder did not affect seed germination or inoculum viability. However, one week at 40°C significantly decreased the viability of the inoculum by 31%. Fungus growth and chlamydospore germination were also reduced by temperatures of 34 and 36°C. M12-4A was susceptible to the fungicide thiram (ED50 = 38.5mug). Field trials were conducted in Mali to evaluate the large-scale efficacy of the seed coating technology. F. oxysporum M12-4A was detected from some S. hermonthica tissue and soil samples using specific primers and Real Time PCR.
31
Jablonski, Leanne M. "Reproductive response to elevated CO2 : the roles of vegetative carbon storage, nitrogen and seed traits." Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=34646.
Full textAbstract:
This study focused on the reproductive response to elevated CO2 of plants possessing below-ground storage. I tested the hypotheses that under elevated CO2: (1) Plants with greater non-foliar storage capacity win show more reproductive response and (2) The altered foliar physiology of carbon (C) and nitrogen (N) use will cause increases in seed number and quality. Carbon dioxide treatments of High (650 muL L-1) and Ambient (360 muL L-1) were used in a controlled environment, simulated growing season, and in a natural pasture community. Hypothesis 1 was tested experimentally using four Raphanus varieties that differed in hypocotyl and leaf sizes. N fertilization and harvest times were used to obtain a range of root:shoot ratios. Enhancements in vegetative leaf area rather than the hypocotyl predicted reproductive responsiveness to CO 2. However, after three years of CO2 exposure in the pasture, hypocotyl-storing Taraxacum officinale responded strongly in vegetative biomass which correlated with inflorescence size and number. Fitness was enhanced four-fold, while the leaf-storing Plantago major produced more ramets and had only a two-fold fitness increase. Hypothesis 2 was tested by examining the C and N physiology underlying the vegetative organs and seeds of the pasture plants. Under elevated CO2, photosynthesis increased two-fold and senescence was delayed. Total plant C:N ratio did not differ, suggesting N acquisition increased. N similarly limited seed number in all cases suggesting an unchanged Physiology of N use in reproduction. While morphology constrained total biomass response, provisioning to seeds increased as shown by higher seed mass and number and decreased variability in number and mass. In all cases, leaf mass increase under high CO2 corresponded with fitness increase. Phenology constrained response to CO 2 as there was no plasticity in flowering day in Raphanus and Plantago, while there were flowering delays but greater seed maturation rate in Tar
32
Dang, Thi Hue. "Supply of affordable high quality potato seed for potato production in the Red River Delta of Vietnam." Curtin University of Technology, Muresk Institute, 2008. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=118348.
Full textAbstract:
Poor quality seed is the major constraint limiting both the productivity of potato crops and the expansion of the potato industry in Vietnam. Despite numerous attempts to establish a certified seed system, the most practical solution is to import clean foundation seed of the desired variety and physiological age. With imports from Europe and North America proving to be immature and too expensive, Western Australia (WA) has emerged as a potential source of high quality seed. While seed imports from WA are unique in that the varieties imported have been selected by researchers in Vietnam as being suited to the agro-ecological environment in the Red River Delta (RRD), no assessment of the economic benefits to smallholder potato farmers from the use of WA potato seed has been undertaken. In 2006/08, the yield and profitability of three potato varieties Eben, KT3 and Atlantic in two locations were compared where the crops had been derived from new seed imported from WA (VN0), seed derived from crops cultivated in the RRD after one generation (VN1) and two generations (VN2). There was a significant difference in the yield produced between the three different seed sources but not between the locations. For all varieties, and in both years, the yield decreased with the number of multiplications in Vietnam. Furthermore, the marketable yield declined significantly from the first crop (VN0) to the third crop (VN2). The decline in yield and tuber quality with each successive generation was associated with an increase in PVY and PVX infection. Not unexpectedly, differences in yield and marketable yield between the seed generations had a significant impact on the gross income for each variety.VN0 seed of all varieties produced the highest gross income (VND 2.4 to 4.1 M/sao) compared to VN1 (VND 1.9 to 3.1 M/sao) which was significantly higher than VN2 (VND 1.4 to 2.4 M/sao). However, while high quality seed is more productive, it is also more expensive. As a result, significant differences were observed between the seed costs. VN0 seed was almost two times more expensive (VND 10,500 – 11,000 per kg) than VN1 and VN2 seed (VND 6,000 – 6,500 per kg). Despite the higher costs, VN0 seed provided the highest net incomes compared to VN1 which was significantly higher than VN2. Farmers who retained seed received a higher net income (VND 0.13 – 0.6 M/sao) than those who did not retain seed. Ways to improve the accessibility of affordable, high quality potato seed to farmers in the RRD are discussed.
33
Baye, Tesfaye. "Exploration, genetic diversity and seed quality analyses in Ethiopian populations of Vernonia galamensis /." Göttingen, Germany : Cuvillier Verlag, 2004. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=012832467&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
Full text
34
de, Oliveira Jose T. A. "Seed lectins : the effects of dietary Phaseolus vulgaris lectins on the general metabolism of monogastric animals." Thesis, University of Aberdeen, 1986. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU367276.
Full textAbstract:
Rats, mice, pigs, quails, chickens, steers and even some insects are unable to grow properly and in some cases die when fed on diets containing raw kidney bean (Phaseolus vulgaris). Although this problem has been extensively studied the precise mechanism of the interference of dietary antinutritional factors with the growth and health of these animals or insects is still not completely understood. In the present work, the toxic effects of the purified kidney bean globulin lectins upon the general metabolism of the rats were studied. The results of the experiments indicated that both qualitatively and quantitatively most of the deleterious effects of raw kidney bean feeding to rats could be accounted for by the inclusion of the pure lectin into nutritionally adequate semi-synthetic diets based on high-quality proteins such as egg albumin. These effects included: (a) a drastic depletion of storage lipid and glycogen and loss of body protein. (The rate of the catabolism of lipids was considerably higher than that of any other body constituent.); (b) a large loss of skeletal muscle (indicated by the change of muscle mass and atrophy of gastrocnemius and plantaris muscles); (c) enlargement of the small intestine, liver and pancreas and involution of the thymus; (d) increased excretion of faecal and urinary nitrogen with a consequently poor nitrogen retention; (e) increased 3-hydroxybutyrate output, and (f) changes in blood concentrations of pancreatic hormones. The magnitude of most of these effects was dependent upon the dietary concentrations of kidney bean globulin lectins (PHA). Thus the extent of the depletion of body lipid and glycogen, loss of muscle, enlargement of the small intestine, liver and pancreas, the extent of the thymus atrophy as well as the increased faecal and urinary nitrogen and increased urinary 3-hydroxybutyrate outputs were shown to be directly correlated with the dietary PHA concentration. In contrast to the deleterious effects of fully active, native PHA, the aggregated lectin preparation (UPHA) did not cause any significant antinutritional effects. The overall results indicated that raw kidney bean is toxic mainly because of its lectin constituent and that local (gut) and systemic adverse reactions caused by PHA account for most of the deleterious effects of this potentially important source of dietary protein for animals and humans.
35
Mukisira, Ephraim Amiani. "The influence of alkaloids on voluntary intake and performance by ruminants fed diets containing lupin seed in Kenya." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41730.
Full textAbstract:
Lupin seed has the potential to be used as a protein supplement in ruminant rations, but its usage is restricted by the presence of alkaloids. Experiments were conducted with the aim of determining whether the removal of specific toxic alkaloids, lupanine and 13-hydroxylupanine, from crushed lupin seed (CLS) would improve the organic matter intake (OMI) and average daily gains (ADG) in lambs, and also improve the lactation performance in dairy cows. Effects on liver function in lambs were also investigated. An additional study on the effects of the detoxification of CLS on the degradation of protein was conducted. In Experiment 1, 30 growing Corriedale lambs were fed five diets for 105 d according to a randomized complete block design (RCBD) with six blocks. Two diets contained intact CLS at 15% (LUI-15) or 30% (LUI-30) of DM; two other diets contained detoxified CLS at 15% (LUD-15) or 30% (LUD-30) and the control (CON) diet was supplemented with crushed sunflower seed, which was locally prepared, on-farm. All diets were formulated to be isonitrogenous (16% CP). The alkaloid content (lupanine and 13-OH lupanine) of the diets was.31,.70,.21 and.52% for LUI-15, LUI-30, LUD-15 and LUD-30, respectively. Thus, diets containing detoxified CLS contained approximately 30% less alkaloids than those with intact CLS. Estimates of ADG of lambs fed diets containing detoxified CLS was higher (P $<$.01) (120 g.d$ sp{-1}$) than that of lambs fed intact CLS (76 g.d$ sp{-1}$). The OMI (73 g/Wkg$ sp{0.75}$) was also higher, although not significantly, for lambs fed diets containing detoxified CLS. Feed conversion efficiency was increased (P $<$.05) by the detoxification of CLS. Lambs fed diets containing intact CLS consumed more OMI as time progressed, suggesting that adaptation to CLS might have occurred. Lambs fed diets containing intact CLS demonstrated increased trends in the activity in plasma of the enzymes glutamic oxaloacetic transferase (GOT) and $ gamma$-glutamyl transfer
36
Baloch, Abdul Hameed. "Effects of seed size and a fungal pathogen, Colletotrichum coccodes, on population dynamics of velvetleaf (Abutilon theophrasti Medic.)." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=36949.
Full textAbstract:
Experiments were conducted in controlled and field conditions to determine the effect of seed size, a fungal pathogen (Colletotrichum coccodes), and soybean interspecific competition on the population dynamics of Abutilon theophrasti (velvetleaf). Seed size differences among ten individual A. theophrasti plants significantly (P < 0.001) affected seed germination and dormancy. Higher seed viability (98%) was observed among seeds having a weight above 6.0 mg. The response of A. theophrasti plants that originated from two extreme seed size groups (small <7mg and large >12mg) to the pathogen, C. coccodes, did not change over generations, and the most vigorous plants produced heavier seeds regardless of the initial seed size or infection with C. coccodes. Under field conditions, the application of C. coccodes and the herbicide, bentazon, did not affect the vegetative and reproductive biomass of A. theophrasti plants when grown in monospecific stands. However, a split application of C. coccodes and bentazon significantly reduced the aboveground biomass and reproductive output of A. theophrasti plants when grown in competition with soybean. The frequency distributions of A. theophrasti plant height, aboveground biomass, and stem diameter were positively skewed (L-shaped) when competing with soybean. However, A. theophrasti plant height and stem diameters were negatively skewed (J-shaped) and the aboveground biomass was positively skewed (L-shaped) in monospecific stands. The allometric relationships of A. theophrasti aboveground biomass and stem diameter in comparison with plant height were curvilinear when grown alone and when in the presence of soybean. However, aboveground biomass and stem diameter showed a simple linear relationship on a log-log scale in both monospecific stands and in competition with soybean.
37
Näslund, Magnus. "Deep photometry of galaxies : to see or not to see /." Stockholm : Univ, 1998. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=008209942&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
Full text
38
Gaol, Mangadas Lumban. "Ecological study of plant species at Sandford Rocks Nature Reserve (SRNR)." Curtin University of Technology, Department of Environmental Biology, 2002. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=13955.
Full textAbstract:
The ecology of plant species at Sandford Rocks Nature Reserve (SRNR) was studied. The study site is an important nature reserve that contains relatively undisturbed natural vegetation. It has a mosaic of exposed granite rocks, scrublands and woodlands. The study involved: a description of the structure and composition of the vegetation; the population characteristics of selected Acacia species; aspects of reproduction in Acacia; germination and seedling characteristics of some Acacia and grass species that dominate the reserve; the effect of seed size on germination and seedling characteristics; and, the relationship of seed size to seed coat thickness in selected Acacia species. Five different areas were studied using the point centered quarter method to sample the woody perennial species. Thirteen Acacia species were examined for reproduction characteristics; and in 2 selected Acacia species, the effects of phyllode and/or inflorescence removal on reproduction was investigated. Germination tests were conducted to identify germination characteristics in 8 Acacia and 7 grass species dominant at SRNR. The possible effects of variation in seed size on germination; seedling characteristics; and, seed coat thickness were investigated in Acacia fauntleroyi and Acacia prainii. A total of 85 species from 20 families of woody perennials were collated. All areas were dominated by the Myrtaceae, Mimosaceae and Proteaceae families. There was considerable variability in the structure and composition of vegetation. Most species were present in particular sites and the composition of communities appears to be related to the heterogeneity of the habitat within the reserve. In areas of shallow or rocky soil, vegetation types present include Allocasuarina huegeliana woodland, Grevillea paradoxa low scrubland and Acacia neurophylla medium shrubland.In a seasonally wet area, vegetation types present include low open grassland; Eucalyptus capillosa (wandoo) woodland; and, Acacia saligna thicket. In deep, dry sandy soil, vegetation types include Phebalium tuberculosum shrubland, Acacia acuminata and Acacia coolgardiensis thickets. On relatively flat areas that gain water from adjacent large granite hills, the vegetation consists mainly of tall, open woodlands of Eucalyptus species. Vegetation types include: medium tall Eucalyptus salmonophloia woodland with Kunzea pulchella shrubland at the periphery of the Eucalyptus woodland. At rock areas, vegetation types present include dense Leptospermum erubescens thicket, low open Acacia prainii and Dodonaea viscosa shrubland. Of the Acacia populations studied, in A. lasiocalyx no recent seedling establishment was observed. It is hypothesised that recruitment occurs in particular periods. As the plants are associated with rock and soils are generally shallow, it appears that recruitment depends on run-off water from the rocks in winter. Continuous recruitment seems to be the pattern in A. prainii with both seedlings and saplings represented. A. fauntleroyi forms relatively small populations; apparently long drought periods (>l00 d) result in mass death and limit its population size. In A. hemiteles, no seedling stage was found, root competition (for water) from associated Eucalyptus species presumably limits its recruitment. Reproductive success of Acacia is affected by rainfall. A wet winter is required to induce flowering and further rain is required after flowering to promote pod development and good seed set.
All Acacia species suffer from drought in the reproduction season, however they differ in their degree of susceptibility. Leaflessness and tree shape also affect Acacia fecundity. Plants bearing more phyllodes produce more flowers and pods, and branches in the upper part of the crown bear heavier inflorescences. In 1998, all Acacia species at SRNR produced mature seed of low weight, with many immature and diseased seed, which gave poor germination. A late spring frost in 1998 is believed to be responsible for limited seed development. In two selected Acacia species, removal of phyllodes reduced the number of pods produced. Presumably, phyllode removal reduces photosynthate produced, therefore the competition among inflorescences (or pods) for resources is more intense and subsequent abortions are likely to occur. All Acacia species studied showed best germination in the cool winter temperature range. Apparently, seeds are adapted to germinate in winter when seasonal moisture is more likely to be available. The best temperature however, varied slightly between species. The grass species dominant in the reserve, except for Aristida contorta, also had more germination in cooler rather than warmer temperatures. The flora of SRNR is similar to typical vegetation of the Southwest. Generally, Acacia species are present only in particular sites, presumably were habitat moisture allows. Seedlings of Acacia species growing in naturally dry areas have greater root: shoot masses than those growing in seasonally wet areas. Biomass partitioning is an apparent strategy to conserve water. Of the 7 grass species, Amphipogon strictus appears to have fastest growth.
Eriachne ovata has greater root than shoot mass, while in all other species, shoot mass is greater than root mass; a characteristic of species that grow well in moist habitats. The longest shoots and roots are in Austrostipa elegantissima, an understorey species of eucalypt woodland. In A. fauntleroyi, the degree of hard-seededness varies between seed sizes. There is a higher proportion of soft seed in smaller seed. Seed of different sizes show some responses to different pre-treatments and incubation temperatures for germination. Larger seeds generally germinate in greater numbers after higher treatment temperatures. The best treatment for small seeds is pre-treatment at 75°C and incubated at 15°C. For medium and large seed, best pre-treatment is at 75°C with incubation at 30°C or soaking in boiling water and incubation at either 15 or 3°C. In A. prainii, seed size; pre-treatment; incubation; and, their interaction all affected germination; larger seeds are more viable. The best treatment to promote germination of A. prainii is soaking in boiling water and incubation at 25°C. In both A. fauntleroyi and A. prainii, larger seeds produce larger seedlings. Seedlings from large seeds have the potential for more rapid pre-photosynthetic growth. Larger, heavier seed has a thicker seed coat. The seed coat of A. prainii is thicker than in A. fauntleroyi; the difference in seed coat thickness is reflected by more soft seed in A. fauntleroyi (35%) than in A. prainii (6%).
39
Batt, Peter J. "Building close and long-lasting relationships with focal customers : an empirical study of seed potato purchasing by Filipino potato farmers /." Curtin University of Technology, Muresk Institute, 2003. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=14229.
Full textAbstract:
In the highlands of the Northern Philippines, a model of long-term relationships between potato farmers and their preferred seed suppliers is proposed. In the absence of any certified seed system that might provide some guarantee of seed quality, farmers prefer to transact with those seed suppliers with whom they have had some favourable prior experience. Such suppliers provide both the best quality seed and, since most farmers must borrow the capital to purchase the seed, the most favourable terms of repayment. As there is much uncertainty in the exchange, the farmer's relationship with their preferred seed supplier is based on trust. However, since the farmer's satisfaction with the exchange cannot be ascertained until after purchase, trust is antecedent to satisfaction. As satisfaction is derived from the economic benefits the farmer obtains, satisfaction will lead to the farmer's desire to maintain the relationship. Satisfaction is enhanced both by the seed supplier's willingness to extend credit and to provide information. As there is much variation between alternative seed supplier's offer quality, satisfaction will result in the farmer becoming more dependent upon that seed supplier who makes the best offer. Furthermore, having provided the farmer with financial assistance, seed suppliers will find that they have constrained their opportunities to use coercive influence strategies, for in the absence of any formal contract, farmer's may readily default on the loan. The use of coercive influence strategies will reduce both the farmer's trust in their preferred seed supplier and the farmer's desire to maintain the relationship.While trust is more important in the transitional economies, critical problems emerge with the use of standardised item measures and scales developed in the industrial countries. Cultural specific adjustments are necessary to ensure social constructs such a trust are functionally equivalent. However, in the context of long-term relationships where satisfaction is also cumulative, introducing measures of both economic and social satisfaction have the potential to overlap with the generally accepted measures of trust.
40
Gurmu, Mulugeta. "The effects of seed vigour and moisture stress on the germination and seedling establishment of wheat and sorghum." Thesis, University of Aberdeen, 1991. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU031802.
Full textAbstract:
The experiments reported in this thesis assessed vigour differences between seed lots of wheat and sorghum under suboptimal conditions. A vigour assessment for each lot of both species was quantified by calculating a value for the viability equation constant Ki. Imbibition of seed lots at lower water potentials reduced water uptake, radicle and coleoptile emergence and their subsequent extension. Similarly, seeds aged by controlled deterioration also resulted in reduced radicle and coleoptile emergence and growth compared to that of unaged seeds. The critical water potential for radicle emergence, coleoptile emergence and their subsequent extension was lower for sorghum than that required for wheat. In both species coleoptile emergence and its subsequent extension was more sensitive than radicle emergence and extension. Tolerance of desiccation of both species decreased as germination progressed. However, imbibition of seeds for 24 h and drying back to their original moisture content promoted seed invigoration in some cases. Cells from seminal roots of wheat and sorghum were shorter when imbibed in lower water potentials than when they were imbibed at higher water potentials. The high drought tolerant cv (DJ1) showed lower root solute potential than the low drought tolerant cv (IS9). The results discussed in this thesis indicate that the information derived from controlled deterioration might be used as an indicator of planting value under sub-optimal conditions.
41
Qian, Jiajing. "Effects of Hordeum vulgare and Hordeum bulbosum genotypes, seed age, culture methods and plant growth regulators on barley haploid production." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=56678.
Full textAbstract:
Four experiments were conducted with the objectives of (i) comparing the suitability of various H. bulbosum clones for haploid production, (ii) determining the parental effects of H. bulbosum and barley genotypes on percentage of pollinated florets yielding caryopses with rescuable embryos and on embryo viability, (iii) comparing different stages for embryo culture and caryopsis culture, and (iv) attempting to produce barley haploids directly from cultured immature caryopses. The results demonstrated: that reproductive characteristics of H. bulbosum clones varied with environmental conditions; that the hybrid H. bulbosum clones MBC-3 and MBC-4 were superior to their parents Cb2920 and Cb2929 as pollen donors; that both parental genotypes and date of harvesting after pollination had large effects on percentage of pollinated florets yielding caryopses with rescuable embryos and on embryo viability; that haploid plantlets can be generated from haploid caryopsis culture without embryo rescue, but only at a low frequency and with a slow rate of germination.
42
Denti, Daniela. "The influence of male and female strobilus production on rates of self-fertilization in a clonal white spruce seed orchard /." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66076.
Full text
43
Causse, Vincent. "The role of substrate characteristics in Populus tremuloides (MICHX.) seed germination in post-disturbance black spruce-feathermoss forest in northwestern Quebec /." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100782.
Full textAbstract:
Trembling aspen (Populus tremuloides (Michx.)) has become established along a mining road in the lower northern Quebec region (49°39' to 49°45'N and 79°01' to 79°02' W) in areas that have not supported aspen in the past. The primary means of regeneration of aspen is through vegetative root suckers, but it is doubtful that it could progress through this region at such a fast rate solely by asexual reproduction. Aspen are known to produce large amounts of seeds that could account for aspen's rapid progression, but sexual reproduction of aspen is rare; very little is known about Populus tremuloides seed germination and seed survival in natural conditions. The aim of this study was to determine seedbed conditions that facilitate the emergence and survival of Populus tremuloides seedlings, and to identify the key factors involved in these processes. Observations of established saplings and a sowing experiment were conducted on both post harvest and post fire sites. Our data on established saplings showed that there were seed-origin trembling aspen located in both post-harvest and burned areas indicating that Populus tremuloides can and has established from seed in areas where aspen was previously absent. Both our sowing experiment and our greenhouse experiment showed that the emergence of seedlings was relatively low, but that Polytrichum strictum moss and exposed mineral soil depressions were the best seedbeds for seed germination. Extreme temperatures and availability of moisture appeared to be controlling factors on seed germination, but ultimately the physical and biological characteristics of each substrate influenced the substrate's response to these factors in a different way. We conclude that sexual reproduction of trembling aspen may and has occurred in this region, and is promoted by the presence of exposed mineral soil and Polytrichum strictum moss.Keywords: Bryophytes, Populus tremuloides, Polytrichum, Sphagnum, seedling, seedbed, germination, seed.
44
Arsovski, Andrej Adam. "Identifying novel genes involved in the synthesis, secretion and modification of cell wall components in the seed coat of «Arabidopsis thaliana»." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=92159.
Full textAbstract:
Plant cells are encased within a complex polysaccharide wall that not only strengthens the plant, but also has key roles in plant growth, cell differentiation, and defence. The plant cell wall is comprised of a network of cellulose microfibrils interconnected by hemicelluloses; this framework is embedded in a more soluble pectin matrix. This dynamic structure is under continual modification during plant growth and development, and its synthesis and modification requires the activity of a myriad of enzymes. Recent research has provided insight into how plants manufacture and regulate the cell wall during development, but much remains unknown. The mucilage secretory cells (MSCs) of Arabidopsis thaliana are used as a model to discover novel genes involved in the synthesis, secretion and modification of cell wall components, particularly pectin. These cells synthesize copious amounts of pectinaceous mucilage during development and, upon hydration of the desiccated seed, this mucilage rapidly swells, bursts from the MSCs and surrounds the seed in a gelatinous capsule. The patchy (pty)/beta-xylosidase1(bxl1) mutant has a peculiar phenotype where mucilage release is patchy and slow, and mutant seeds are delayed in germination. Cloning of the mutant locus revealed a lesion in an encoded bifunctional β-xylosidase/α-arabinofuranosidase. Chemical and immunological analyses indicate an increase in 1,5-linked arabinans, suggesting the action of AtBXL1 is required for the trimming of these chains to allow correct mucilage release. In addition to the study of AtBXL1, an enhancer/suppressor screen of the mum4 reduced mucilage mutant was performed in order to identify novel genes involved in mucilage secretory cell differentiation. The screen identified six novel mutants named mum enhancer (men) 1-6. Characterization of men mum4 double mutants revealed two distinct groups, those that produced similar amounts of mucilage to mum4 but failed to release it (men2, 6), andLes cellules végétales sont encastrées dans une paroi de polysaccharide complexe qui non seulement renforce la plante mais aussi agit de façon cruciale dans les mécanismes de croissance, de différentiation cellulaire et de défense. La paroi des cellules végétales consiste en un réseau de microfibrilles de cellulose connectées par des hemicelluloses. Ce réseau est encastré dans une matrice de pectine plus solubilisable. Cette structure dynamique est en modification perpétuelle pendant le développement et la croissance de la plante. Ces changements et sa synthèse engage l'action d'une myriade d'enzymes. Des études récentes ont données de nouvelles perspectives sur comment les plantes produisent et régulent leur paroi cellulaire pendant le développement cependant beaucoup reste à découvrir. Les cellules sécréteuses de mucilage (MSCs) d'Arabidopsis thaliana sont utilisées comme modèles pour la découverte de nouveaux gène impliqués dans la synthèse, sécrétion et la modification des composants de la paroi cellulaire, particulièrement la pectine. Ces cellules synthétisent de grandes quantité de mucilage pectiné durant le développement et, après hydration de la graine disséquée, celui-ci gonfle rapidement, jaillit des MSCs entourant la graine d'une capsule gélatineuse. Le mutant patchy (pty)/beta-xylosidase1(bxl1) présente un phénotype particulier où le relargage est épars et lent, ces graines présentent aussi un retard dans la germination. Le clonage du locus muté a révélé une lésion dans la β-xylosidase/α-arabinofuranosidase bifonctionelle transcrite. Les analyses chimique et immunologique ont indiquées une augmentation des 1,5-linked arabinans suggérant que l'action de BXL1 est requise pour l'hydrolyse de ces chaines permettant un bon relargage du mucilage. En parallèle de cette étude, un screen des enhancers/suppresseurs du mutant au mucilage réduit mum4 dans l'intention d'identifier des nouveaux gènes imp
45
Baxter, Alyssa. "Adolescent non-suicidal self-injury: willingness to seek school-based help." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66957.
Full textAbstract:
Non-suicidal self-injury (NSSI) is a prevalent behaviour among high school-age youth; however, there remains confusion concerning the optimal sources of support and treatment for these adolescents. The current study sought to investigate how many adolescents with NSSI are willing to access help at school, as well as the variables related to their willingness to do so. Overall, 13.5% of the students who reported engaging in NSSI indicated that they were willing to seek help at school. The rate of help-seeking did not differ by gender or indices of NSSI severity, including the frequency of NSSI and number of body locations employed. Students who indicated that they would seek help had more people in their lives that knew about their NSSI, were more likely to report having been victimized at school, and indicated that they were more worried about some violent events occurring in their neighborhood, such as gang violence.Bien que l'automutilation non suicidaire soit un comportement assez répandu au sein des adolescents au secondaire, il existe toujours des questions quant aux meilleurs moyens de prévention et d'intervention auprès de ces adolescents. Le présent sondage visait à déterminer combien d'adolescents qui s'automutile sont prêt à chercher de l'aide à leur l'école ainsi qu'a déterminer les facteurs qui influencent cette décision. Au total, 13,5% des adolescents qui se sont automutilés ont affirmé être prêt à chercher de l'aide à l'école. Ce taux est constant parmi les garçons et les filles, et n'est pas influencé par le degré de sévérité de l'automutilation, ni par la fréquence ou le nombre d'endroits du corps mutilés. Les étudiants ayant indiqué vouloir obtenir de l'aide ont davantage des personnes dans leur vie qui sont au courant de leur automutilation, ont rapporter avoir été victime de violence à l'école plus souvent et se sont montrés plus préoccupés par la violence de quartier, notamment celle perpétrée par les gangs de rue.
46
Barfurth, Marion A. "The collaborative process as seen through children's disagreements while learning science." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28674.
Full textAbstract:
The emphasis in mathematics and science education on children actively constructing their own knowledge, collaborating with each other and in contexts that are technologically rich is resulting in new classroom dynamics. Often portrayed as a series of polite exchanges, this study aims to advance our understanding of the collaborative learning process. It does this by looking at a less frequently reported event, children's disagreements while learning science. Following a proposal for conceptually advancing the field the research questions addressed include: (a) Looking at the importance and nature of children's disagreements during a design and construction task using LEGO/Logo and (b) Using the proposed analytic framework to see what it tells us about the collaborative process during children's disagreements. The findings suggest that looking at a disagreement from a social and cognitive move perspective provides an effective framework for looking at the collaborative process. It revealed that disagreements can be a legitimate form of collaboration and elementary school children's disagreements, while on task, can be both extensive and constructive.
47
Fotheringham, Diane. "Confident to seek help : developing skill with the use of feedback." Thesis, University of Strathclyde, 2012. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=17402.
Full textAbstract:
Healthcare within the UK is undergoing a transformation in terms of traditional role and skill assignations of staff, with an attendant blurring of boundaries seen in terms of the practice of skill in many clinical settings. This has implications for the development and future learning of the staff involved and the aim of this study is to explore how feedback from a supervisor is used to develop and sustain skill in a group of nurses and, in this way, examine the interaction between the learner, the supervisor and the context in which the learning is set. This thesis uses a social constructivist stance and a mixed method approach to answer research questions set. 85 nurses were invited to undertake a web-based questionnaire and semi-structured interviews were conducted on ten of the respondents. The themes which emerged were: developing identity and fitting in; mining tacit knowledge and managing ambiguity; support versus dependency; and, finally, the development of judgement. The study reveals a group who learn in a context that they find enjoyable and is often conducive to learning. The participants are well motivated to learn and they have access to the skills and knowledge of experts. However, learning is also seen to be dominated by the context in which it is set and as the participants learn motor skills, they also learn to fit in and manage a brittle working environment. This thesis illustrates an aspirational professional group for whom the governance of learning leads the participants to be confident to seek help. The thesis concludes by suggesting changes to the pedagogical model employed and avenues for further research.
48
Sutherland, Alexander Mackenzie. "The Brahan Seer : the making of a legend, c1570-2001." Thesis, University of Aberdeen, 2005. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU206015.
Full textAbstract:
This thesis traces the legend of the Brahan Seer between the sixteenth and twenty-first centuries. It considers the seer figure in relation to aspects of Highland culture and society that shaped its development during this period. These include the practice and prosecution of witchcraft; the reporting of and scientific investigation of instances of second sight; and the perennial belief in and use of prophecy as a means of predicting events. In so doing the thesis provides a set of historicised contexts for understanding the genesis of the legend and how it changed over time. It also makes a contribution to the debates about not only witchcraft, second sight and prophecy but also the relationship between 'popular' and 'elite' culture in Scotland. By taking the Brahan Seer as a case study it argues that 'popular' culture is not antithetical to 'elite' culture but rather in constant (and complex) interaction with it.
49
MacQuarrie, J. A. "Selective chemical control of quack grass Agropyron repens (L.) Beauv. in seed production fields of birdsfoot trefoil Lotus corniculatus (L.) cv. Leo." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66254.
Full text
50
Duers, Lorraine Elizabeth. ""To see oursels as ithers see us!" : an exploration of student nurses' conceptions and implementation of peer review and self-assessment." Thesis, University of Strathclyde, 2013. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=22643.
Full textAbstract:
Engagement with peer review and self-assessment potentially influences the development of self-regulatory capability (Nicol, 2010; Sadler, 2010; Boud, 2007) and therefore could be beneficial to student nurses who at the point of professional registration are required to demonstrate this capability (Nursing and Midwifery Council (NMC), 2010). However, engagement with peer review is not always a positive experience for learners. A negative peer review experience can result in loss of confidence, decreased self-esteem and withdrawal from the learning process (Duers and Brown, 2009; Ecclestone and Pryor, 2003). The aim of this qualitative research study was to explore student nurses' (n=25) conceptions and implementation of peer review and self-assessment; an area that was identified as being under-researched (Rout and Roberts, 2007). Ethical approval was obtained. Adoption of a non-probability, purposive sampling technique permitted selection of participants undertaking a pre-registrat ion nursing programme within a Higher Education institution. Data collection took place on 34 occasions, utilising focus group discussion, practical task and individual interview methods. Data analysis involved the application of six main concepts derived from the theories of the Zone of Proximal Development (Vygotsky, 1978) and Symbolic Interactionism (Blumer, 1969) to transcribed data. A potential limitation of concept-driven data analysis is its minimising effect on the emergence of new material directly from the data (Tappen, 2011), therefore Miles and Huberman (2004) 3 stage analysis model was also utilised. The study contributes empirical evidence of student nurses' conceptions and implementation of peer review and self-assessment. A new feedback form was created and used by participants during the study; a form created by student nurses for use by student nurses in the future. Recognition of the potential of peer review and self-assessment engagement to influence the development of self-regulatory capability was verbalised by participants during the study.