Limited information exists regarding the processing parameters and extent of reinforcing potential natural fibers have in polymer matrices. The five natural fiber mats studied were low shive flax, mid shive flax, high shive flax, hemp and kenaf. The parameters characterized were fiber size, wax content, surface contact angle, and shive content. The compressive force and unsaturated permeability was measured for each mat, and composites were constructed and tested using selected mats in a soy-based polyurethane (PU) matrix. All mats exhibited a viscoelastic behavior under compression, and an increase in shive content correlated with an increase in relaxation. The presence of shive and larger fiber size increased the permeability. Higher wax content and contact angle lowered the permeability. The mechanical properties for all composites performed better than the neat PU, showing there was matrix to fiber adhesion and load transfer. Hemp outperformed the other fibers studied in all mechanical tests.

No description available.

No description available.

Arbuscular mycorrhizal fungi (AMF) play an important role in nutrient cycling and growth of flax (Linum usitatissimum L.). However, limited information is available regarding the symbiotic association between flax and AMF in field environments. A study was conducted to survey AMF communities colonizing flax grown in Saskatchewan. Additionally, field and growth chamber studies investigated the impact of AMF inoculation on nutrient uptake and growth of flax. Eighteen commercial flax fields were surveyed to assess mycorrhizal colonization of flax and to assess the impact of agricultural practices and soil abiotic factors on AMF activity. The flax root-associated AMF communities were explored using a 454 sequencing method, together with microscopic-based measurements of root AMF colonization and soil spore density. High levels of root colonization were detected in most flax fields. Of the 222 AMF operational taxonomic units (OTUs) identified in flax roots, 181 OTUs clustered as Funneliformis-Rhizophagus, 19 as Claroideoglomus, 14 as Paraglomus, six as Diversisporales and two as Archaeospora. Results suggest that tillage influenced the composition of AMF communities colonizing flax, and reduced relative AMF abundance and species richness. Additionally, AMF community characteristics were related to soil abiotic factors such as pH, EC, available phosphorus and nitrogen. Field experiments were conducted over two years (two sites per year) using a commercial AMF inoculant applied at three rates (0, 1X, and 2X the recommended rate) with or without P fertilizer (16.8 kg ha-1). The response of flax cultivars to AMF inoculation was examined in a growth chamber experiment. In addition, 454 sequencing was employed to examine the impact of AMF inoculation on root-associated AMF communities. Under field conditions, only one site showed increased root colonization with AMF inoculation. Flax responded to AMF inoculation differently under different field conditions. At the two sites with intermediate initial soil P level, evidence of increased above-ground biomass and plant nutrient uptake with AMF inoculation was observed. However, such an effect was not detected when P fertilizer was combined with the inoculation. At a low P site and an irrigated site, P application accounted for all of the increases in plant nutrient uptake and biomass of flax, whereas no responses to AMF inoculation were detected. The 454 sequencing revealed different inoculation-induced changes in the diversity and composition of root-associated AMF communities between sites, which was possibly related to different field environments and native AMF communities. In the growth chamber, AMF inoculation resulted in general increases of plant nutrient uptake among cultivars, but only one cultivar showed enhanced biomass with inoculation. The diversity of AMF communities colonizing different flax cultivars was generally reduced by AMF inoculation. Community composition shifted under AMF inoculation, and the shifts appeared to be cultivar specific. These results suggested that benefits of AMF inoculation in flax production are limited and currently not predictable, and the degree of response is likely dependent on a myriad of soil and environmental conditions.

Fiber flax (Linum usitatissimum L.) production in the Willamette Valley ended in Oregon around 1957 before newly developed technology and fiber cultivars were available. The purpose of this research was to explore the use of modern methods and new cultivars. Field studies were conducted to evaluate cultivars and optimum cultural practices that would produce the highest yield and best fiber quality in the Willamette Valley on Woodburn silty clay loam. A study was conducted to assess the winter hardiness of fifty flax cultivars. The effect of four different pull dates on straw and fiber yield and fiber quality were investigated at two sites in 1995 and 1996. Pulling in stage 2, 3, or 4 resulted in an increase in straw yield over pulling in stage 1 in 1996. No differences were detected in fiber yield or caustic weight loss in response to pull date in either year. An acceptable pulling window is stages 1-3 (range of 900 to 1300 growing degree days). Retting took 13 weeks in both years. Rainfall during the retting period was 10.7 cm in 1995 and 6.9 cm in 1996. A field study was conducted in 1995 and 1996 to test the effect of three nitrogen (N) levels (50, 75, and 100 kg ha�����) and three fiber flax cultivars (Ariane, Cascade, and Viking) on straw yield. There was a significant increase in yield with increased N levels in 1996. Higher levels of N increased yield in all three cultivars in both years. Lodging of 'Cascade' increased with increased N levels in 1995. The effect of three planting dates on yield and stand density of Ariane fiber flax were investigated in 1995. The 31 March planting date produced the most retted straw (9704 kg ha�����). A fall-planted winter cultivar experiment was conducted during 1994-95 and 1995-96. In 1994-95, four varieties (Ariane, Texala, Viking, and Hyslop Cascade) had greater winter survival than Linore, the check variety. Only Linore withstood the second winter. / Graduation date: 1997

The object of this study was to identify microscopic differences among six selected cultivars of harakeke traditionally used by Maori in weaving. The cultivars were Arawa, Makaweroa, Paretaniwha, Takaiapu, Takirikau, and Tapamangu. The effectiveness of different microscopy techniques for taking measurements of the dimensions of ultimate fibres using a factorial experimental design was investigated in part A. Constant variables were geographical location, location of specimens along the leaf, season (winter), individual plant, fan, north-facing fan, and age of plant (approximately seven years), and cultivars (Paretaniwha and Tapamangu). Experimental variables were the microscopy techniques used and measurement axis. Techniques selected use on further cultivars in part B were transverse sections of leaf specimens 4 m thick, embedded in Paraplast� and observed using LM, and non-fixed ultimate fibres observed using SEM. In part B the dimensions of ultimate fibres from the six selected cultivars of harakeke were measured, and analysed (ANOVA and Tukey's HSD), and the transverse section shapes of fibre aggregates were observed. Transverse widths of ultimate fibres ranged from 10.15 m (Takaipu) -12.80 m (Paretaniwha). Ultimate fibre lengths ranged from 3735 m (Takirikau) - 4751 m (Makaweroa). The cultivars prizes for muka, Arawa and Makaweroa, had the longest and finest ultimate fibre bundles more uniform in transverse-sectional shape than the other cultivars studied and perhaps this explains their selection for extraction of muka. Takirikau had a high yield of ultimate fibre bundles, and perhaps this makes extraction of muka worthwhile. Paretaniwha differed from the other five cultivars studied having an average number of ultimate fibre bundles per unit width that were narrow and non-uniform in shape, and composed of short, thick, ultimate fibre cells. The microscopic structure of muka from six selected cultivars of harakeke used traditionally for weaving varied and may explain differences perceived by weavers, and that different end uses are preferred for various cultivars.

Flax (Linum usitatissimum L.) is being considered as a platform crop for the development of bioproducts. Potential benefits of bioindustrial farming include the provison of bioenergy and biomaterials, and opportunities for biorefining. Prior to the commercialization of crops intended for bioproducts however, the safety of the food/feed system and the environment must be assured. As part of a preliminary biosafety assessment I conducted a literature review and experiments to quantify seed-mediated gene flow from flax to the environment and food/feed system. Flax seed losses at harvest, seed persistence in soil, efficacy of herbicides to control volunteer survival and fecundity in subsequent crops, volunteerism (density and occurrence) and volunteer emergence periodicity in follow crops in commercial fields were examined. Total seed losses at harvest in commercial fields were variable (2.7 to 44.2 kg ha-1). Flax has a short longevity in the seed bank (2 to 3 years). Flax has been selected for reduced seed dormancy and volunteer flax seed persistence may be hastened by burial. Compared to other domesticated crops, flax has a prolonged period of emergence and calculated EM50 values (the growing degree days required for 50% emergence) ranged from 227 to 340 growing degree days (GDD). Flax volunteers reached their period of peak emergence earlier in conventional tillage than in reduced tillage fields. Volunteer flax densities were highest prior to herbicide applications (10.4 to 570.2 plants m-2) in all fields the year following flax production (2005) and diminished over time. Volunteers that emerge in the spring may be controlled with registered herbicides. Glyphosate and fluroxypyr tank-mixed with either monohydrate sodium salt of 2,4-dicholorophenoxy acetic acid (2,4-D) or monochlorophenoxyacetic acid Ester 500 (MCPA) were most effective in reducing volunteer flax density, biomass, and fecundity. These herbicides also reduced the adventitious presence of volunteer flax seed in spring wheat (from over 8.5% to 0.16%). Best management practices could be adopted to mitigate seed-mediated gene flow from flax in agricultural productions systems, but thresholds of zero are not biologically realistic. The agronomic baseline data generated in this thesis however, suggests that flax may be an appropriate crop platform for bioindustrial products. / Plant Science

Cyclolinopeptides (CLs) are hydrophobic cyclic peptides found in flaxseed. They show immunosuppressive activity, but the biological function of these compounds is largely unknown. This thesis presents the results of studies that were conducted to determine whether CLs could act as antioxidants. In the first study, flaxseed oil was passed over a silica adsorbent column to remove polar compounds. The polar compounds were then eluted from the silica absorbant using a series of increasingly polar solvents. Individual polar fractions were then added back to the silica-treated flaxseed oil and the oxidative stability index of these samples was determined at 100 °C. A polar fraction containing mainly CLA, β/γ- and δ-tocopherol increased the induction time of silica-treated flaxseed oil from 2.3 ± 0.28 h to 3.2 ± 0.41 h. A positive effect of the polar fraction containing a mixture of CLA and CLD-CLG on the oxidative stability of oil was also observed. The antioxidant mechanism of CLs was investigated in several model systems using electron spin resonance spectroscopy. The concentration of radicals in a DMPO (5,5-dimethyl-1-pyrroline-N-oxide) radical-CLs reaction mixture was monitored. All CLs exhibited dose dependent scavenging activities. CLA–CLC reactions with DMPO-OH at a concentration of 5 mM resulted in a 24–30% decrease in electron paramagnetic resonance (EPR) signal intensity. The reaction of CLs and the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH•) revealed a more complex interaction than simple radical scavenging. Peptides (CLG and CLG") that contained both tryptophan and methionine showed stronger radical scavenging activity than did CLs containing methionine or methionine sulfoxide but not tryptophan (CLB and CLC). Irradiation of the reaction mixture of DPPH• and peptide with UV light also affected the radical scavenging behaviour. Scavenging activities of DPPH• by CLB, CLC and CLA were enhanced by light, whereas scavenging of DPPH• by the tryptophan containing peptides CLG and CLG″ was not affected. High-performance liquid chromatography with mass spectrometry (HPLC-MS) analysis of the reaction mixtures after a radical scavenging reaction was used to determine the impact of radical scavenging on the peptides. These reactions revealed new masses that were identified and characterized. It was established that DPPH• reacted with the methionine of CLB and with tryptophan in CLG and CLG, by formation of a new covalently-bonded species. Covalent linkages between these amino acids (alone or in peptides) and DPPH• have not been reported previously.

In Canada, flax (<i>Linum usitatissimum</i> L.) is grown for its seed oil. However, a major disadvantage associated with growing oilseed flax is that the straw is difficult to incorporate into the soil after harvest. Instead, the majority of flax straw is burned in the field, increasing the workload for farmers, as well as creating air pollution. Agronomic concerns are also associated with burning, since it leaves fields vulnerable to wind and water erosion. A small market exists for Canadian flax straw for making high quality paper products and some plastic composites. However, fibre-based and fibre-using industries are growing world wide, and flax straw fibre is becoming an important product. Flax straw fibre concentration varies among cultivars and environments. Consistently high fibre concentrations are essential if the fibre in oilseed flax is to become an important product for Canadian farmers. This study assembled the agronomic information necessary to select for increased straw fibre concentration in the Crop Development Centre (CDC) Flax Breeding Program. Three experiments were conducted to determine: how seeding rate and row spacing effects straw fibre concentration, the effects of seeding date on straw fibre concentration, and how nitrogen fertilizer rates effects straw fibre concentration. Seeding in mid-May at either an 18 or 36 cm row spacing at a seeding rate of 30 or 45 kg/ha resulted in high straw fibre concentration without reducing other important oilseed characteristics such as seed yield, oil content and straw fibre yield. Nitrogen fertilizer did not have an effect on either straw fibre concentration or straw fibre yield.

Canada has been recognized as the largest exporter of flax seed in the world. Currently, very little flax straw is further processed, despite its potential as a value added product, with only about 7-10% of Canadian flax seed producers harvesting residual flax straw rather than burning the straw. A traditional use of flax straw has been for the production of fibre for the linen industry. Interest in flax fibre has been rekindled with the impetus to seek out bioproducts that replace non-renewal resources and provide value-added opportunities for agricultural producers. Flax fibre also has a range of potential uses in automotive parts, geotextiles, insulation material, etc. Despite this potential, the Canadian flax fibre sector remains largely underdeveloped, with fledgling supply chains and lack of investment in the necessary processing capacity. This paper develops a framework for analysing the relational exchanges at different stage of the supply chain to determine if the paucity in investment is the result of prohibitively high exchange costs. A number of distinct stages in the flax fibre supply chain can be identified: farmers producing flax seed and/or straw; processors who extract the natural fibre from the straw; and manufacturers who use the fibre in their products. The paper develops a framework that draws together insights from Transaction Cost Economics, Agency Theory and Bargaining Theory. The role of institutions in facilitating quality measurement and providing participants with information is also considered. The theoretical framework identifies asset specificity, agency measurement costs, bargaining power and under-developed institutions as key factors in the development of the flax fibre sector. From the theoretical framework, a set of propositions is developed that examine the anticipated effect of these factors on vertical coordination in the sector. The theoretical propositions are explored through a series of semi-structured interviews with parties at each stage of the supply chain (producers, fibre processors, final manufacturers), as well as with industry experts. Information from the interviews is used to identify the transaction characteristics and the institutional framework characterizing the flax fibre sector in Canada. This is analysed through a comparative case study approach with the flax fibre sector in Europe, and the wool fibre sector in New Zealand as an example of a fully developed and long-standing fibre sector. By also noting the different vertical coordination strategies that are present in these supply chains, a connection is drawn between the presence of certain transaction characteristics and the corresponding cost-minimizing exchange relationships. The case studies are used to investigate the propositions developed from the theoretical framework regarding the impact of transaction characteristics on the optimal vertical coordination strategy and the impediments to development and investment in the sector. The propositions developed in the framework are verified to a great extent by the comparative case study. The uncertainty in the exchange environment regarding the future direction of the flax fibre industry and the high measurement costs due to the absent quality and grading regime in the Canadian flax fibre set the two industries apart from each other. Both of these dimensions impact the exchange costs of a transaction and subsequently, the extent to which the parties are closely coordinated. The case studies verify that using a framework to analyze transactions provides additional insights because of the joint consideration of several features of the transaction.