Broomrapes, <i>Orobanche</i> spp., are holoparasites that affect the growth of a variety of broadleaf crops. One of the distinct characteristics of the family Orobanchaceae is the lack of chlorophyll, and hence inability to synthesize their own food. Broomrapes subsist on the roots of the host plant from which they derive the carbon, water, and nutrients needed for further growth. Parasitism as such leads to yield reductions, and in case of heavy infestations, complete crop failure. Among other plants parasitized by broomrapes are several legumes, some of which are also the world's most economically important crops. As part of their unique biology, legumes provide an ecological niche for diazotropic soil bacteria, which belong to the family Rhizobiaceae. In return, the host plant receives fixed nitrogen from the nodules, specialized structures produced on the roots of most legume plants upon inoculation with bacteria. <i>Orobanche</i> spp. germination depends on the presence of chemical stimulant in host root exudates. It has been reported that inoculation of some legumes resulted in greater infestation by parasitic weeds. In addition, bacterial nodules were assumed to provide a place for broomrape invasion of host legume. Furthermore, infestations were observed to be more intense in aerobic conditions when rhizobia are most active. It is possible that production of the stimulant could be correlated with the infection of roots with <i>Rhizobium</i>, and that the nodules formed on the roots could play a role in broomrape parasitism; however, others have not confirmed this. Studies were conducted to investigate the possibility of interaction between <i>Orobanche</i> spp. attack and <i>Rhizobium</i> nodulation in legumes. Seed germination, number of parasitic attachments, as well as the morphology of two broomrape species, small broomrape (<i>Orobanche minor</i> Sm.) and Egyptian broomrape (<i>Orobanche aegyptiaca</i> Pers.), were studied. <i>O. minor</i> showed a greater percent seed germination, and formed a greater number of attachments on red clover (<i>Trifolium pratense</i> L.) inoculated with <i>Rhizobium leguminosarum</i> bv. <i>trifolii</i> in comparison with non-inoculated plants. However, the addition of the inoculum did not appear to enhance <i>O. aegyptiaca</i> seed germination or the number of its attachments on the host roots compared with the controls. Morphological observations of <i>O. minor</i> attachments on red clover suggest that parasitic attachments were not situated over the bacterial nodules, but perhaps involve parasite-induced enzymatic degradation followed by mechanical protrusion of host plant root cortex, possibly utilizing host plant-rhizobacteria interactions as well. / Master of Science

Small broomrape, a holoparasitic weed, is a relatively new weed introduction in the Pacific Northwest that has contaminated a limited number of red clover fields in Oregon. Greenhouse and field studies were conducted to evaluate small broomrape response to common crop and weed species in the Pacific Northwest. Host species in the greenhouse or field study included alfalfa, arrowleaf clover, carrot, celery, common vetch, crimson clover, lettuce, prickly lettuce, red clover, spotted catsear, subterranean clover, white clover, and wild carrot. False-host species included barley, birdsfoot trefoil, creeping bentgrass, cucumber, field corn, fine fescue, flax, Italian ryegrass, nasturtium, oat, orchardgrass, perennial ryegrass, snap bean, sugar pea, sunflower, sweet corn, tall fescue, tomato, and wheat. Non-host species included sugar beet and curly dock. The greenhouse polyethylene bag system provided a rapid and inexpensive screening for plant species host status to small broomrape. Germination and attachment to host roots are initiated by chemical exudates, that may change concentration in response to nutrient availability and microorganisms. Red clover was grown in varying concentrations of ammonium sulfate fertilizer with and without Rhizobium inoculation, and with small broomrape seeds. Neither Rhizobium inoculation nor ammonium concentration influenced the number of small broomrape attachments to red clover roots. A survey was conducted of red clover seed growers with small broomrape-contaminated fields in the Pacific Northwest. Red clover seed from six respondents were cleaned at the same cleaning facility, and the same respondents purchased their seed stock from this cleaning facility. Small broomrape was not identified in red clover fields prior to or during the first clover seed harvest of fall planted red clover in small broomrape-contaminated sites. / Graduation date: 2003

Field studies were conducted in Ontario in 2009 and 2010 to determine the tolerance of winter wheat to herbicide-fungicide tank-mixtures, and the tolerance of winter wheat underseeded red clover to commonly used herbicides applied at three timings. Tank-mixtures including the fungicide tebuconazole caused injury at early and late timings, while mixtures including the herbicide bromoxynil/MCPA were most injurious when applied late in the season. Injury was transient with no yield reductions observed. MCPA/mecoprop/dicamba caused significant yield reductions when applied at normal and late timings, but did not reduce yield when applied early. The herbicides prosulfuron+bromoxynil and pyrasulfotole/bromoxynil were most injurious to underseeded red clover and reduced clover biomass regardless of application timing. Herbicides and herbicide-fungicide tank-mixtures applied early, during cold temperatures do not increase winter wheat or red clover sensitivity; the likelihood of injury is greatest when applications of these products occur late. / Grain Farmers of Ontario; Ontario Ministry of Agriculture, Food, and Rural Affairs; Agriculture Adaptation Council of Canada

This research assessed the seasonal effects of contrasting tillage and crop rotation systems on soil ammonia oxidizing bacteria (AOB) and archaea (AOA). Four different cropping systems under till and no-till were analyzed in a 30 year-old agricultural field trial. Samples were collected during the 2010 growing season at times corresponding with agronomic events. Nucleic acids were preserved in the field and subsequently analyzed by quantitative real-time polymerase chain reactions (qPCR). Tillage decreased AOB activity and abundance in the plow layer (0-15 cm) immediately after fall moldboard plow events, but observed AOB dynamics at other times suggest tillage had a long-term distribution effect across depth (0-30 cm). AOA abundance was significantly greater in no-till plots at all times indicating tillage had longer-term effects on these communities. Crop rotation had minimal effect on AOB and AOA, but there was a noted yield advantage for corn following wheat, regardless of tillage treatment. / OMAFRA Highly Qualified Personnel Program, NSERC

Stressors in the aquaculture environment can lead to negative impacts on growth and immune health, resulting in susceptibility to infectious diseases. These stressors are expected to increase as the growth of aquaculture continues to rise to meet demands for quality fish protein. Isoflavones, as a crude extract or as a pure isolate, may be effective in modulating the stress response, promoting growth and immunity. The objective of these studies was to examine the effect of various pure isoflavone isolates and crude isoflavone extracts on stress, growth, and immunity. Nile tilapia (Oreochromis niloticus) were stressed by adding hydrocortisone to the feed. In a 7-week study, pure isoflavone isolates of genistein and puerarin were evaluated to determine their respective effects on stress, growth, and immunity. A separate 10-day physiological and 6-week growth study focused on crude isoflavone extracts from kudzu (Pueraria lobata), red clover (Trifolium pratense), and soybean (Glycine max) was performed to determine their respective effects on stress, growth, and immunity. Numerous physiological parameters of the fish were measured (serum cortisol concentration, blood glucose concentration, hematocrit, hepatosomatic index, plasma protein concentration, lysozyme activity, and spleensomatic<br>index) to determine the effects of these pure isoflavone and crude isoflavone extracts on the modulation of stress and immunity. Many growth parameters were examined (length, weight, condition factor, weight gain, specific growth rate, feed intake, feed conversion ratio, and protein efficiency ratio) as well to determine the effects of these pure isoflavones and isoflavone extracts on growth. The addition of isoflavone and crude isoflavone extracts to the diet of Nile tilapia ameliorated some of the negative consequences of stress. Compared to stressed fish fed commercial feed, genistein and puerarin added to the diet appeared to improve serum cortisol concentrations, which resulted in increased plasma protein, albeit at different durations of stress. Puerarin, as well as all three crude isoflavone extracts, significantly increased spleen-somatic index compared to non-supplemented stressed fish, although the crude isoflavone extracts did not appear to improve serum cortisol concentrations. Crude isoflavone extracts also showed overall increases in lysozyme activity compared to non-supplemented stressed fish, although this was not significant. Genistein, puerarin, and red clover showed increased growth rates, feed conversion ratio, and protein efficiency. Overall, pure isolates of isoflavone appear to be more effective in modulating stress, immunity, and growth than the crude isoflavone extracts, although red clover extract showed promises in the ability to modulate the stress response and improve growth and immunity. There are likely substantial interactions between the isoflavones in the crude extracts that cannot be fully understood by measuring the effects of single isoflavones. Regardless, isoflavone supplementation (pure or crude) appeared to generally have an overall positive impact on stressed Nile tilapia, requiring more research to better understand the effects and mechanisms behind these isoflavones.

Submitted by Maria Beatriz Vieira (mbeatriz.vieira@gmail.com) on 2017-06-06T14:03:30Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) tese_fernanda_reolon_tonel.pdf: 1524534 bytes, checksum: 4326518bd7bd55acb90e0f2630de6ac4 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-06-06T14:30:22Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) tese_fernanda_reolon_tonel.pdf: 1524534 bytes, checksum: 4326518bd7bd55acb90e0f2630de6ac4 (MD5) / Made available in DSpace on 2017-06-06T14:30:22Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) tese_fernanda_reolon_tonel.pdf: 1524534 bytes, checksum: 4326518bd7bd55acb90e0f2630de6ac4 (MD5) Previous issue date: 2014-12-08 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / O estudo objetivou avaliar a capacidade fitorremediadora do trevo vermelho (Trifolium pratense L.) e do feijão miúdo (Vigna unguiculata L.) a compostos derivados de petróleo. Foram realizados experimentos em laboratório e em casa de vegetação, onde as sementes das duas espécies foram expostas as concentrações de 0,0; 0,1; 0,2 e 0,3 % (v/v) de óleo diesel e em seguida submetidas às análises de viabilidade, vigor e atividade de enzimas hidrolíticas. Em uma segunda etapa, as duas espécies, foram submetidas à contaminação por 0,0; 0,5; 1,0 e 1,5 % (v/v) de óleo diesel. O trevo vermelho foi cultivado durante 112 dias e a partir de coletas periódicas foram realizadas análises de parâmetros de crescimento, teor de pigmentos fotossintéticos, anatomia foliar e radicular e análise de enzimas antioxidantes. O feijão miúdo permaneceu em casa de vegetação durante 60 dias, para as análises periódicas dos parâmetros de crescimento, teor de pigmentos fotossintéticos, fotossíntese e enzimas antioxidantes. Para ambas, no início e no final do experimento foi realizada análise de hidrocarbonetos de petróleo no substrato de cultivo. Os resultados obtidos mostraram maior sensibilidade das duas espécies submetidas ao contaminante em condições controladas, no entanto, a influência negativa foi observada apenas nas maiores concentrações do composto tóxico. Os demais parâmetros foram diferentemente influenciados nas duas espécies, destacando-se para ambas, os efeitos negativos ocorridos na maior concentração de óleo diesel (1,5 % (v/v)) e benefícios ocasionados na menor concentração (0,5 % (v/v)). Portanto, os efeitos fisiológicos ocasionados permitiram a determinação do limite de tolerância das plantas de trevo vermelho e feijão miúdo ao óleo diesel. A eficiência na remoção dos compostos tóxicos, verificada para as duas espécies permitiu a confirmação de ambas como fitorremediadoras de compostos derivados de petróleo. / The study aimed to evaluate the phytoremediation capacity of red clover (Trifolium pratense L.) and cowpea (Vigna unguiculata L.) derived from petroleum compounds. Experiments were conducted in laboratory and greenhouse, where the seeds of both species concentrations of 0.0 were exposed; 0.1; 0.2 and 0.3% (v/v) of diesel and then subject to feasibility analysis, strength and activity of hydrolytic enzymes. In a second step, the two species were submitted to contamination by 0.0; 0.5; 1.0 and 1.5 % (v/v) of diesel oil. Red clover was grown for 112 days and from periodic samples were taken analyzes of growth parameters, photosynthetic pigments content, leaf and root anatomy and analysis of antioxidant enzymes. Cowpea remained in a greenhouse for 60 days for regular reviews of the growth parameters, photosynthetic pigments content, photosynthesis and antioxidant enzymes. For both the beginning and end of the experiment was performed petroleum hydrocarbon analyzer in the cultivation substrate. The results showed higher sensitivity of both the dopant species under controlled conditions, however, the negative effect was observed only at higher concentrations of the toxic compound. The other parameters were influenced differently in the two species, standing out for both the negative effects occurring in the highest concentration of diesel (1.5 % (v/v)) and benefits incurred in lower concentration (0.5 % (v/v)). Therefore, the physiological effects caused allowed the determination of the tolerance limit for red clover plants and cowpea to diesel oil. The efficiency of removal of toxic compounds found in these species permitted confirmation both as phytoremediator of petroleum compounds.

No description available.

Manure and underseeded clover are sustainable N sources for spring wheat on gleysolic soils of the St. Lawrence lowlands. Farmers rely on little information to manage adequately, these alternatives to fertilizer N. This study documents in spring wheat red (Triticum aestivum L. cv Algot) (i) the agronomic value of (Trifolium pratense L. cv Arlington); (ii) the impacts of application time and underseeded clover an manure N recovery; (iii) the residual NO3-- in the soil profile that constitutes a potential risk of N transfer from soil to air and water associated to clover alone or combined with manures and, (iv) the use of a plant N availability index. A four year field experiment was established an a St. Urbain clay (Orthic Humic Gleysol) at St. Bruno de Montarville (45°33'N; 73°21'W) in 1993. Ammonium nitrate at 0 to 160 kg N ha--1, swine liquid manure (SLM) and dairy solid manure (DSM) were used either alone or in combination with clover ploughed down in fall as green manure. Manures were applied at pre-seeding, in post-emergence or after harvest. The impact of clover on wheat yield was related solely to an improved N nutrition. Clover supplied fertilizer N equivalents of approximately 30 kg ha --1 to the succeeding wheat crop. Clover combined with manures increased available N in the soil profile so that estimated recovery of manures N was strongly reduced in 1995. Apparent N recovery of SLM was higher than for DSM with values of 5% and 17% in 1994 and 1995 compared to 2 and 4% for DSM. Application time did not significantly affect manure N recovery. Limited risk of N transfer to water and air was associated with post-harvest manure application and underseeded red clover because those practices increased soil profile NO3-- in fall and the end of April. Fluxes of N estimated by NH4+ and NO3 -- sorbed in situ on ionic exchange membranes (IEMs) provided better monitoring of N released by added organic N sources than N extracted by 2M KCl and also were bette

Next generation sequencing is a modern method applied in plant virology for sensitive detection of previously characterized and novel pathogens without any preceding knowledge of them. In this study three novel and two already described viruses were detected by de novo assembly of Illumina single-end reads ( Hi-Seq 2500 system) from total poly(A) enriched RNA of diseased red clover (Trifolium pratense) and indicator plant (Nicotiana occidentalis 37B). The complete genomic sequence of novel Red clover carlavirus A (RCCA) was determined from Illumina reads, 5´, 3´ RACE, cloning, RT-PCR and Sanger sequencing. The presence of RCCV was also confirmed in mechanically inoculated tobacco plant.

Les hydrocarbures aromatiques polycycliques (HAP) sont des polluants organiques persistants potentiellement mutagènes et cancérigènes. Leur transfert de l’atmosphère vers les écosystèmes, notamment vers les plantes, conditionne leur entrée dans les chaines alimentaires mais les modalités de ce transfert restent encore mal connues. L’objectif de ce travail était donc de caractériser le transfert et d’identifier les effets biologiques des HAP atmosphériques sur un système sol-plante-microorganismes symbiotiques.Un dispositif expérimental a été conçu afin de recréer en laboratoire une pollution atmosphérique par les HAP avec comme HAP modèle le phénanthrène (PHE). Le dispositif a fait l’objet d’une validation et d’une calibration élaborée de manière originale par une double approche mêlant l’expérimental à la simulation mathématique. Les niveaux d’exposition en polluant (150 µg m-3), contrôlés par des échantillonneurs passifs, se sont avérés pertinents par rapport aux conditions in situ. Ce dispositif a donc été utilisé pour exposer durant un mois des microsystèmes sol-plante-microorganismes au PHE par voie atmosphérique.Les différentes études ont mis en évidence un transfert du PHE depuis l’atmosphère vers tous les compartiments du microsystème, avec une accumulation majeure vers les feuilles de trèfle ou de ray-grass (respectivement 170 et 70 µg g־ ¹MS) et un transfert phloémien vers les racines est suggéré. Chez le trèfle, la mycorhization n’a pas été affectée, tandis que le nombre de nodules actifs a diminué de manière significative. Contrairement aux racines, la biomasse aérienne du trèfle a été significativement affectée (environ – 25%) par l’exposition au PHE atmosphérique, suggérant un impact sur le métabolisme carboné de la plante. Une expérience de marquage des trèfles au ¹³C-CO2 a effectivement montré un impact négatif du PHE atmosphérique sur la croissance, l’allocation de biomasse et l’allocation carbonée. Pour conclure, ces études ont permis non seulement de caractériser les effets biologiques et physiologiques des HAP atmosphériques sur les végétaux mais également de proposer l’utilisation du potentiel mycorhizien comme indicateur de pollution atmosphérique par les HAP. / Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants potentially mutagenic and carcinogenic. Transfer from the atmosphere to ecosystems, especially to plants, conditioning their entry into food chains, but the terms of this transfer are still poorly understood. The aim of this study was to characterize the transfer and identify the biological effects of atmospheric PAHs on soil-plant-symbiotic microorganisms.An experimental device was designed to recreate in the laboratory air pollution with phenanthrene (PHE) as a model PAH. The device was been validated and a calibration developed in an original way by a dual approach combining the experimental mathematical simulation. The levels of exposure to pollutant (150 mg m־³), controlled by passive samplers, were relevant with field conditions. This device has been used to expose a month of the soil-plant micro-organisms in the PHE through the air.Various studies have demonstrated a transfer of PHE from the atmosphere to all compartments of the microsystem, with a major accumulation to leaves in clover or ryegrass (respectively 170 and 70 µg g ־¹ dry weight) and a phloemic transfer to the roots is suggested. In clover, mycorrhization was not affected, while the number of active nodules decreased significantly. Unlike roots, aboveground biomass of clover was significantly affected (approximately – 25%) by exposure to air PHE, suggesting an impact on the carbon metabolism of the plant. A labelling experiment with ¹³C- CO2 in clover has actually shown a negative impact of PHE air on growth, biomass and carbon allocation.In conclusion, these studies have not only characterized the biological and physiological effects of atmospheric PAHs on plants but also proposed the use of mycorrhizal potential as an indicator of air pollution by PAHs.