Made available in DSpace on 2014-08-20T13:42:10Z (GMT). No. of bitstreams: 1 Dissertacao_Diego_Batista_Zeni.pdf: 366485 bytes, checksum: 6607655f98dea67ee4ce2ba69cb56557 (MD5) Previous issue date: 2010-06-30 / The storage of grain for longer periods, especially those containing high content of oil to manufacture biodiesel, generated a major difficulty of the production chain in the stage of post-harvest, where there are few data on drying and storage of oilseeds with maintaining their technological characteristics. The aim of the work, we study the effects of canola grain temperature in grains dried at temperatures of 20- 25, 35-40, 55-60 and 75-80°C, were stored for periods of 1, 100, 200 and 300 days in both environments with relative humidity 55-65% and 75-85%, and temperature controlled of 21±3°C. Were analyzed moisture, bulk density and oil content of grains and also its acidity, peroxide value, saponification and iodine oil canola grain stored subjected analysis of variance (ANOVA) of data, by Tukey test (P<0,05). We conclude that: A) the drying temperature in grains causes more damage than immediate dormant grains. B) the relative humidity in the storage environment alters the equilibrium moisture content of grain density, oil content and hydrolytic and oxidative stability. C) the storage time is more important in the stability of oil in the grain mass during drying temperatures above 40°C and storage environment with relative humidity above 70%. D) drying temperature with a mass greater than 60ºC only allow oil stability of grain in storage with humidity below 70% and up to 200 days. / A armazenagem de grãos por períodos mais longos, principalmente os que contém alto teor de óleos para a fabricação de biocombustível, gerou uma maior dificuldade da cadeia produtiva na etapa de pós-colheita, onde há poucos dados referentes a secagem e armazenamento de grãos oleaginosos com manutenção de suas características tecnológicas. Objetivou-se, com o trabalho, estudar nos grãos de canola os efeitos da temperatura na massa de grãos secados as temperaturas de 20-25, 35-40, 55-60 e 75-80°C, armazenados por períodos de 1, 100, 200 e 300 dias, em ambientes com umidade relativa do ar de 55 a 65% e 75 a 85% e temperatura controlada de 21±3°C. Foram analisados umidade, massa volumétrica e teor de óleo dos grãos e também índices de acidez, peróxidos, saponificação e iodo do óleo dos grãos de canola armazenados e submetidos análise de variância (ANOVA) dos dados, pelo teste de Tukey (P<0,05). Conclui-se que: A) a temperatura de secagem na massa de grãos provoca mais danos latentes do que imediatos nos grãos. B) A umidade relativa do ar no ambiente de armazenamento altera a umidade de equilíbrio dos grãos, a massa específica, o teor de óleo e a estabilidade hidrolítica e oxidatíva. C) O tempo de armazenamento é mais influente na estabilidade do óleo dos grãos em secagens com temperaturas de massa superiores a 40ºC e armazenamento em ambiente com umidade relativa do ar superior a 70%. D) Secagens com temperatura de massa superior a 60ºC só possibilitam estabilidade do óleo dos grãos em armazenamentos com umidade menor que 70% e até 200 dias.

To improve understanding of the effectiveness of host resistance against Leptosphaeria spp., three aspects of effectiveness of resistance were investigated. With focus on the major Rlm-mediated resistance against L. maculans, changes in effectiveness of Rlm7-mediated resistance to prevent initiation of disease epidemics at the leaf spot stage were investigated in winter oilseed rape field experiments at five sites in the UK over the period with the cropping seasons 2009/2010 - 2013/2014. L. maculans isolates virulent against Rlm7 were identified in the UK. This may be associated with observed changes in lesion phenotypes on the Rlm7 cultivars in field conditions. However, despite increased severity of phoma leaf spotting on Rlm7 cultivars, there was no associated increase in phoma stem canker severity at the end of the cropping seasons. The effectiveness of winter oilseed rape cultivars for control of phoma stem canker (caused by L. maculans or L. biglobosa) was affected by the coexistence of the two Leptosphaeria species in oilseed rape crops. Weather conditions influenced ascospore release of both species and favoured L. biglobosa ascospore release in 2011, resulting in subsequent increased L. biglobosa phoma leaf spotting and stem canker severity. However, coexistence of Leptosphaeria spp. on oilseed rape crops was affected by the cultivar resistance against L. maculans. CE experiments showed that there were interactions between the two Leptosphaeria spp. in planta. Their coexistence on B. napus was influenced by the different host responses that they trigger during host colonisation. Effects of increased temperature on effectiveness of resistance against L. maculans and on severity of symptoms by Leptosphaeria spp. on B. napus were investigated. Increased temperature affected both Rlm4- and Rlm7-mediated resistance, when assessed by phenotypic and molecular techniques. Increased temperature was associated with increased symptom severity, for both L. maculans and L. biglobosa lesions on plants. Cultivar quantitative resistance background increased effectiveness of resistance against phoma stem canker pathogens at increased temperature and should be deployed in in strategies for adaptation to climate change to avoid increased phoma stem canker epidemics in the future.

Masters of Science / Bacterial endophytes are able to improve the growth of their hosts through a number of different mechanisms such as nutrient uptake regulation, plant hormone production and regulation, siderophore production and phosphate solubilisation. They have also been shown to be able to provide protection to plants against various abiotic stressors, through various means such as oxidative stress protection. The purpose of this study was therefore to isolate endophytic bacteria from the stems of different weeds, to characterize their ability to use some of the most important growth promoting mechanisms including the ability to produce IAA, siderophores and ACC deaminase, what effect they had on the nutrient uptake in their hosts and to determine to what extent they could promote growth in the roots, stems and leaves of Brassica napus plants. In addition to this the endophytes were tested to see to what extent they could protect Brassica napus from the negative effects of vanadium stress and how this affected the plant physiologically in terms of morphology, overall biomass, the plants nutrient profile, lipid peroxidation and levels of cell death. The effect of vanadium stress on the oxidative state of Brassica napus was also monitored by determining the levels of stress induced reactive oxygen species (ROS) and the corresponding antioxidants that are responsible for regulating these reactive oxygen species. Six different endophytes (P1, P2, P3, P4, P5, P6) were isolated from different weed samples. Each endophyte was found to be able to significantly improve germination and growth in their host plant. Each isolate was able to improve the uptake of certain macronutrients and micronutrients in their respective hosts, while all of the isolates were shown to be capable of producing siderophores and ACC deaminase. One isolate had high levels of IAA production, with the remaining isolates producing small amounts of IAA. All isolates were also unable to solubilize phosphate. The five best performing endophytes (P1, P2, P3, P5, P6) in the preliminary growth trials were used in the follow up vanadium stressed growth trials, with endophyte P4 being left out of the remaining experiments. All of the endophytes showed improvements in growth promotion in comparison to the control, with endophyte treated plants showing both increased growth and biomass in both the non-stressed and vanadium stressed treatments of the vanadium stressed growth trial; however, the leaves of the vanadium stressed plants were significantly smaller than their non-stressed counterparts. When looking at the oxidative state it was found that vanadium stress caused a significant increase in the development of O2 -, H2O2 and •OH in the control and in addition to this it was shown that treatment with endophytes was able to cause a significant decrease in the levels of stress induced H2O2 and •OH in all of the treatments and O2 - for plants treated with endophyte P5. The noted change in the oxidative state of endophyte treated plants was attributed to an increase in the antioxidant activity of these plants, as it was found that endophyte treated plants showed a combination of increased activity for Superoxide dismutase, catalase and ascorbate peroxidase. This study has shown that endophytic bacteria from plant stems can be used to improve crop growth and yield, while simultaneously producing more nutrient dense crops from the same amount of land. It has also determined that endophytes P1, P2, P3, P5 and P6 are able to successfully provide protection to crop plants from the harmful effects of exposure to vanadium stress. This has great potential for improving food security locally and around the world, by allowing those who cannot gain access to large amounts of food to take in more nutrients from the same amount of food. Furthermore, it also presents the opportunity to use endophyte treatments to grow crops on land that has been previously contaminated with certain heavy metals. / 2023-12-01

>Magister Scientiae - MSc / In an ever changing environment, plants are constantly challenged by various abiotic stresses such as salinity, which limits global crop production. This directly affects food availability for the global population, which is projected to increase to 9.5 billion by 2050, which in turn places great pressure on natural resources and food security. These environmental adversities induce the accumulation of reactive oxygen species (ROS) hydrogen peroxide, hydroxyl and superoxide radicals which cause severe oxidative damage to plants. The equilibrium between the production and detoxification of ROS is then dependent on the modulation of enzymatic and non-enzymatic antioxidants to achieve plant homeostasis. / 2024

Raps wurde als Fallstudie für eine Kulturpflanze ausgewählt, die sich außerhalb des Anbaus spontan etablieren kann und so als Quelle für Neophyten dient. In einer regionalen Studie im Osnabrücker Land wurde basierend auf Kartierungen (2004-2008) und kernkodierten Mikrosatellitenmarkern die Herkunft, Persistenz und genetische Variation verwilderter Rapspopulationen untersucht. Die wichtigsten Quellen für die erhöhte genetische Variation in verwilderten Rapspopulationen waren die mehrfache Einschleppung verschiedener Sorten und Hybridisierungen zwischen diesen. Raps tritt im Osnabrücker Land mit einer Reihe nah verwandter Arten, darunter Brassica rapa und Raphanus raphanistrum, sympatrisch in verwilderten Populationen auf. Hybride zwischen Raps und diploiden Rübsen konnten nachgewiesen werden. Tetraploider Rübsen wurde als Kreuzungspartner von Raps erstmals in dieser Studie untersucht. In Kreuzungsversuchen und in einem Freilandversuch konnten interspezifische Hybridisierungen zwischen tetraploiden Rübsen und Raps nachgewiesen werden. Unter natürlichen Bestäubungsbedingungen im Freilandversuch mit tetraploiden Rübsen-Mutterpflanzen wurde eine Hybridisierungsrate von 16,2% abgeschätzt. Die Untersuchungen zeigen, dass verwilderte Rapspopulationen durchaus ein Potenzial zu evolutiven Entwicklungen besitzen. Verwilderte Rapspopulationen können als Trittsteine für intra- und interspezifischen Genfluss dienen und dadurch beim Anbau transgener Rapssorten die Koexistenz verschiedener Anbauformen erschweren. Sie können die Etablierung von Transgenen außerhalb des Anbaus ermöglichen, die Transgenausbreitung fördern und Introgression in nah verwandte Arten vermitteln. Die Wahrscheinlichkeit von Hybridisierungen zwischen Raps und Rübsen (diploid und tetraploid) könnte verringert werden, wenn vermieden würde, diese kreuzkompatiblen Arten gemeinsam in Saatgutmischungen zu verwenden.

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L'intérêt pour la dispersion des gènes via le pollen a augmenté avec les cultures de plantes génétiquement modifiées. A ce jour, les données expérimentales ainsi que la modélisation portant sur les mouvements du pollen de colza, Brassica napus L., à l'échelle du paysage ne différencie pas clairement la part du vent et des insectes dans cette dispersion. Cependant, l'estimation de la dispersion des gènes par le pollen reste une condition nécessaire pour la gestion des risques d'échappement des (trans-)gènes vers l'environnement et les cultures conventionnelles. A travers cette thèse, nous avons pu mettre en évidence qu'une grande diversité d'insectes pollinisateurs pouvait transporter du pollen viable entre différentes plantes de colza sur des distances importantes (>1.1 km). La diversité d'insectes varie d'une région à l'autre et d'une année sur l'autre. Cependant, bien que la majorité des insectes sur une zone de grande production de colza ait du pollen de cette culture sur leur corps, seulement 39,4 % des insectes capturés sur des plantes mâle-stériles transportent du pollen de colza viable. Bien que nous n'ayons pas pu déterminer avec précision la part du vent et des insectes dans le pollinisation du colza, il semblerait que les insectes participent de façon plus importante à la pollinisation de plantes présentes en bordures de champs, augmentant ainsi le taux de pollinisation croisée. Nos résultats fournissent des données fiables pour améliorer les modèles de dispersion pollinique pour des cultures entomophiles à l'échelle du paysage. Ces modèles sont essentiels pour l'aide à la gestion afin de réduire la dispersion des gènes par le pollen des cultures génétiquement modifiées vers les plantes sauvages ou les cultures conventionnelles

<p>Pollination is one of the most important factors determining the reproductive success of plants. This thesis examines processes associated to varying pollination, with focus on plant responses. The first aim was to examine the possibility and constraints for short-term evolution of flower size in <i>Raphanus raphanistrum</i>. The results showed that there exists a possibility for pollinator-mediated short-term evolution of flower size in the study species. Flower size was strongly correlated to plant size. Since flower size cannot evolve separately from plant size, this correlation may constitute a constraint to the evolution of flower size. The second aim was to determine how varying pollen load affects later flowering, reproduction and growth of maternal plants. High pollen load treatment resulted in larger or more flowers on late flowers, which may enhance pollen dispersal and reproductive success, while the total seed mass was the same between treatments. The results indicate that the study species <i>R. raphanistrum</i>, <i>Sinapis arvensis</i> and <i>Brassica napus</i> have plastic responses in floral traits according to the present pollination level. The third aim was to determine how varying pollen load affects seed quality and offspring vigor. The results suggest that high pollen load had no positive effects on seed quality or offspring vigor due to pollen competition. Instead, seed mass determined seed quality and offspring vigor in the three study species and low pollen load treatment resulted in highquality offspring due to heavier seeds. The fourth aim was to examine causes and consequences of variation in reproductive success of <i>Succisa pratensis</i> on a regional scale. The results suggest that the most important variables, on a regional scale, for reproductive success were population size and habitat quality. The results showed that seed weight variation might be important when assessing reproductive success. In this study, seed weight variation did not seem to be adaptive.</p>

Pollination is one of the most important factors determining the reproductive success of plants. This thesis examines processes associated to varying pollination, with focus on plant responses. The first aim was to examine the possibility and constraints for short-term evolution of flower size in Raphanus raphanistrum. The results showed that there exists a possibility for pollinator-mediated short-term evolution of flower size in the study species. Flower size was strongly correlated to plant size. Since flower size cannot evolve separately from plant size, this correlation may constitute a constraint to the evolution of flower size. The second aim was to determine how varying pollen load affects later flowering, reproduction and growth of maternal plants. High pollen load treatment resulted in larger or more flowers on late flowers, which may enhance pollen dispersal and reproductive success, while the total seed mass was the same between treatments. The results indicate that the study species R. raphanistrum, Sinapis arvensis and Brassica napus have plastic responses in floral traits according to the present pollination level. The third aim was to determine how varying pollen load affects seed quality and offspring vigor. The results suggest that high pollen load had no positive effects on seed quality or offspring vigor due to pollen competition. Instead, seed mass determined seed quality and offspring vigor in the three study species and low pollen load treatment resulted in highquality offspring due to heavier seeds. The fourth aim was to examine causes and consequences of variation in reproductive success of Succisa pratensis on a regional scale. The results suggest that the most important variables, on a regional scale, for reproductive success were population size and habitat quality. The results showed that seed weight variation might be important when assessing reproductive success. In this study, seed weight variation did not seem to be adaptive.

The phytopathogenic fungus <i>Leptosphaeria maculans</i> can cause blackleg disease on crucifers, which results in significant yield losses. Fungal diseases involve interactions between pathogenic fungi and host plants. One aspect of these interactions is mediated by secondary metabolites produced by both fungi and host plants. Phytotoxins and elicitors as well as phytoanticipins and phytoalexins are metabolites produced by fungi and plants, respectively. This thesis describes and discusses the isolation, structure, biological activity and biosynthesis of the secondary metabolites produced by L. maculans.<p> The elicitor-toxin activity bioassay guided isolation of elicitors and phytotoxins produced by <i>L. maculans</i> in a chemically defined medium lead to the isolation of general elicitors, <i>sirodesmin PL</i> (165) and <i>deacetylsirodesmin PL</i> (166), and specific elicitors, <i>cerebrosides C</i> (14) and D (31) from minimum medium (MM) culture under standard conditions. The known phytotoxins sirodesmin PL (165) and deacetylsirodesmin PL (166) induced the production of <i>phytoalexin spirobrassinin</i> (122) in both resistant plant species (brown mustard, <i>Brassica juncea</i> cv. Cutlass) and susceptible plant species (canola, B. napus cv. Westar). A mixture of cerebrosides C (14) and D (31) induced the production of the phytoalexin rutalexin (127) in resistant plant species (brown mustard, B. juncea cv. Cutlass) but not in susceptible plant species (canola, B. napus cv. Westar). New metabolites leptomaculins A-E (267-269, 272 and 274) and deacetylleptomaculins C-E (270, 273 and 275) were isolated from elicitor-phytotoxin active fractions but did not display detectable elicitor activity or phytotoxicity after purification.<p> New metabolites maculansins A (299) and B (300), which were not detected in cultures of L. maculans incubated in MM, were isolated from cultures of <i>L. maculans</i> incubated in potato dextrose broth (PDB). Maculansins A (299) and B (300) displayed higher phytotoxicity on brown mustard than on canola and white mustard (<i>Sinapis alba cv. Ochre</i>) but did not elicit detectable production of phytoalexins in either brown mustard or canola. Metabolite 2,4-dihydroxy-3,6-dimethylbenzaldehyde (212) was produced in higher amount in cultures of L. maculans incubated in PDB than in MM and displayed strong inhibition effect on the root growth of brown mustard and canola. <i>L. maculans</i> incubated in MM amended with high concentration of NaCl produced a new metabolite, 8-hydroxynaphthalene-1-sulfate (293), and a known metabolite, bulgarein (294), which are likely involved in the self-protection. The potential intermediates involved in the biosynthesis of sirodesmin PL (165) were investigated using deuterium labeled precursors: [3,3-2H2]-L-tyrosine (251a), [3,3-2H2]O-prenyl-L-tyrosine (312a), E-[3,3,5,5,5-2H5]O-prenyl-L-tyrosine (312b), [5,5-2H2]phomamide (171a), [2,3,3-2H3]-L-serine (233d) and [5,5-2H2]cyclo-L-tyr-L-ser (252a). Intact incorporation of [5,5-2H2]phomamide (171a) into sirodesmin PL (165) suggested that leptomaculin D (272) and E (274), and deacetylleptomaculin D (273) and E (275) are not intermediates in the biosynthesis of sirodesmin PL (165). They are more likely the catabolic metabolites of sirodesmin PL (165). Phomamide (171), the intermediate in the biosynthetic pathway of sirodesmin PL (165), is likely biosynthesized by coupling of prenyl tyrosine (312) with serine (233) rather than prenylation of cyclo-L-tyr-L-ser (252). When [3,3-2H2]-L-tyrosine (251a), [3,3-2H2]O-prenyl-L-tyrosine (312a), and E-[3,3,5,5,5-2H5]O-prenyl-L-tyrosine (312b) were fed into cultures of L. maculans, a â proton exchange was detected by 1H NMR through intrinsic steric isotope effect, which occurs before the formation of phomamide (171). The biosynthesis and catabolism of sirodesmin PL (165) were proposed based on the results obtained in this work.