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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Desempenho em laboratório e em campo de sementes de milho submetidas a diferentes tempos de envelhecimento

Nogueira, Débora Cristiane [UNESP] 02 September 2011 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:35:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-09-02Bitstream added on 2014-06-13T19:46:24Z : No. of bitstreams: 1 nogueira_dc_dr_ilha.pdf: 465474 bytes, checksum: 73aaf83a41766ac828cf08b26abed5fe (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O uso de sementes com alto nível de vigor é fundamental para o sucesso de um empreendimento agrícola, pois apresentam melhor desempenho em campo, resultando em maior produção. O objetivo do trabalho foi verificar o nível do vigor em sementes de três híbridos de milho submetidas ao envelhecimento acelerado e seus desempenhos em laboratório e em campo. Para tanto sementes dos híbridos AG-5020, AG-8088 e BG-7049 foram envelhecidas artificialmente à 41oC por 0, 48 e 72 horas e secadas em estufa à 38 °C/48 horas para a formação dos diferentes lotes. Experimento 1 – No laboratório, verificou-se o nível de vigor e o desempenho das sementes dos diferentes lotes por meio de análises de germinação, primeira contagem, deterioração controlada, tetrazólio, comprimento de raiz primária e mesocótilo, número de raízes/plântula, massa de matéria seca de plântula e emergência em solo. Experimento 2 – No campo as sementes foram semeadas manualmente em parcelas de 8 linhas de 5m, espaçamento de 0,5m e densidade de 80.000 plantas ha-1. Verificou-se o nível de vigor e o desempenho das plantas em campo pelas avaliações de características morfológicas das plantas, caracteres da espiga e componentes de produtividade. O delineamento experimental foi o inteiramente casualizado com os tratamentos obtidos da combinação 3 x 3 (híbridos x níveis de vigor) com quatro repetições. Em laboratório as sementes mais vigorosas apresentaram melhores desempenhos e em campo proporcionaram a obtenção de maior produtividade, o que se deve principalmente ao maior estande final obtido. As características das plantas e das espigas estão relacionadas ao genótipo de cada híbrido não se verificando efeito do vigor das sementes / The use of seeds with high level of vigor is fundamental to the success of an agricultural development, since its have better performance in the field, resulting in increased production. The objective of this study was to assess the level of vigor in seeds of three maize hybrids submitted to accelerated aging and their performance in laboratory and field. Seeds of AG-5020, AG-8088 and BG-7049 were artificially aged at 41°C for 0, 48 and 72 hours and dried in an stove at 38 °C /48 hours for the formation of the different lots. Experiment 1 – in the laboratory, we found the level of vigor and the performance of different seed lots by means of analysis of germination, first count, controlled deterioration, tetrazolium, length of primary root and mesocotyl, number of roots/seedling, seedling mass dry matter and seedling emergence in soil. Experiment -2 the seeds were manually sown in plots of 8 rows of 5m, 0,5 m spacing and density of 80000 plants ha-1. The level of vigor and performance of plants in the field evaluations of morphological characteristics of plants, components and characters of the spike in productivity. The experimental design was completely randomized treatments obtained with the combination 3 x 3 (hybrid x vigor levels) with four replications. In the laboratory the most vigorous seeds showed better performances and the field higher productivity, which is mainly due to higher final stand. As characteristics of plants and spike are related to the genotype of each hybrid was not observed effect of vigor seeds
32

Conservação da viabilidade de sementes de Senna macranthera por meio de recobrimento / Conservation of viability of Senna macranthera seeds by coating

Pozitano, Marina 10 October 2011 (has links)
Orientador: Sandra Cristina dos Santos Rocha / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-18T23:30:21Z (GMT). No. of bitstreams: 1 Pozitano_Marina_D.pdf: 3604129 bytes, checksum: 7fb79cd92222f6a6e16325ebc4f5fc10 (MD5) Previous issue date: 2011 / Resumo: No processo de recobrimento em leito de jorro, as características físicas das partículas a serem recobertas, a formulação da suspensão de recobrimento e as condições operacionais como vazão do ar, pressão de atomização, vazão da suspensão, temperatura do ar e massa de sólidos são parâmetros importantes que influenciam o desempenho do processo. Para o caso de sementes, o recobrimento pode ser utilizado para facilitar manuseio, transporte, semeadura, proteção contra ataques de insetos e na conservação de espécies para preservação do ambiente. Nesta pesquisa foi estudado o processo de recobrimento de sementes florestais da espécie Senna macranthera em leito de jorro e foram realizadas análises da qualidade fisiológica das sementes in natura e recobertas durante o armazenamento. As sementes desta espécie possuem dormência tegumentar, o que dificulta a germinação devido à impermeabilidade do tegumento. A quebra da dormência utilizada em sementes de espécies florestais tem por objetivo aumentar a porcentagem de germinação das sementes e uniformizar a emergência de plântulas, mas, sem a dormência, essas sementes podem não manter sua viabilidade por longos períodos e o armazenamento torna-se inviável. A primeira etapa deste trabalho envolveu a caracterização física das sementes, a definição das condições de operação do equipamento e o desenvolvimento da formulação da suspensão de recobrimento. Em seguida, as sementes passaram por quebra de dormência por imersão em ácido sulfúrico e foram recobertas com a suspensão polimérica desenvolvida. As sementes recobertas e a testemunha (sementes in natura) foram armazenadas em geladeira convencional, na temperatura de 5 ºC, para início do período de 380 dias de armazenamento. Os resultados da caracterização física para as sementes in natura foram: diâmetro médio de Sauter (3,4 mm), esfericidade (0,52), ângulo de repouso dinâmico (10 º), porosidade (1,81 %), peso de mil sementes (41,05 g) e densidades real, aparente e volumétrica (1397,2; 1371,9; 884,4 kg/m³, respectivamente). Para as sementes recobertas foram obtidos os seguintes valores: diâmetro médio de Sauter (3,7 mm), esfericidade (0,69), ângulo de repouso dinâmico (35 º), porosidade (4,30 %), peso de mil sementes (50,52 g) e densidades real, aparente e volumétrica (1397,2; 1337,2; 795,1 kg/m³, respectivamente). Para operar o equipamento foram definidas uma vazão de suspensão de 2 ml/min, pressão de atomização de 2 psig, temperatura do ar de entrada de 70 ºC e carga de sólidos de 450 g. A suspensão formulada foi composta por: Eudragit FS 30D® (30,6 g), trietil citrato (0,45 g), estearato de magnésio (2,25 g), dióxido de titânio (1,35 g), talco (4,6 g), pigmento rosa (0,15 g) e água (60,6 g). Após o recobrimento as sementes foram analisadas visualmente através das imagens geradas por microscópio eletrônico de varredura. Isotermas de adsorção foram determinadas pelo equipamento Dynamic Vapor Sorption para as sementes in natura e recobertas. Os resultados foram ajustados por cinco modelos de isotermas de sorção: GAB, Caurie, Oswin, Peleg e Smith. Para as sementes in natura, o melhor ajuste foi obtido com o modelo de Peleg (R² = 0,998), enquanto que, para as sementes recobertas o melhor ajuste foi com o modelo de Smith (R² = 0,981). Durante o armazenamento três grupos de sementes foram analisados: o grupo das sementes recobertas; o grupo das sementes in natura (que foram semeadas com a dormência tegumentar) e, por último, o grupo das sementes escarificadas, que corresponde às sementes que foram armazenadas in natura, porém, antes da semeadura foi realizada a quebra da dormência. Durante os 380 dias de armazenagem foram realizados testes de germinação, envelhecimento acelerado e grau de umidade, com periodicidade de aproximadamente 40 dias. Para o período analisado, as sementes in natura apresentaram média de grau de umidade igual a 9,25 %, enquanto que, para as sementes recobertas a média foi de 7,12 %. No final do armazenamento a germinação das sementes escarificadas e das sementes recobertas não apresentaram diferença estatística entre si. Para o teste de envelhecimento acelerado, as sementes escarificadas foram mais vigorosas em relação às sementes recobertas. As porcentagens de germinação e o vigor das sementes semeadas in natura foram inferiores aos demais grupos, pois a dormência tegumentar impediu a absorção de água, componente essencial para que a semente germine / Abstract: For the process of coating in spouted bed, the physical characteristics of the particles to be coated, the formulation of coating suspension and the operating conditions such as the air flow, the pressure of atomization, the flow of suspension, the air temperature and the mass of solids are important parameters that influence the process performance. In the case of seeds, coating can be applied to facilitate handling, transporting and sowing, to protect the seeds against insects and for the conservation of species to environmental preservation. In this work the process of coating of forest seeds of Senna macranthera species in spouted bed was studied and analysis of the physiological quality of covered and in nature seeds during storage were performed. The seeds of this species have tegument dormancy, which hinders the germination due to impermeability of the tegument. The breaking of dormancy in seeds of forest species aims to increase the percentage of seed germination and to uniform the seedling emergence; however, these seeds cannot maintain their viability for long periods and the storage becomes unworkable without dormancy. The first stage of this work involved the physical characterization of the seeds, the definition of operating conditions for the coating process and the development of the formulation of the coating suspension. Then, the seeds underwent to tegument dormancy break by immersion in sulfuric acid before being coated with the polymer suspension developed. The coated seeds and the control (in nature seeds) were stored in conventional refrigerator at a temperature of 5 ºC. The storage period was of 380 days. The results of physical characterization of the seeds in nature were: Sauter diameter of 3.4 mm, sphericity of 0.52, dynamic angle of repose of 10 º, porosity of 1.81 %, weight of thousand seeds of 41.05 g and real, apparent and volumetric densities equal to 1397.2, 1371.9 and 884.4 kg/m³, respectively. For the coated seeds the following values were obtained: Sauter diameter of 3.7 mm, sphericity of 0.69, dynamic angle of repose of 35 º, porosity of 4.30 %, weight of thousand seeds of 50.52 g and real, apparent and volumetric densities equal to 1397.2, 1337.2 and 795.1 kg/m³, respectively. Operating conditions were defined as: suspension flow of 2 ml/min, atomization pressure of 2 psig, inlet air temperature of 70 ºC and load of seeds of 450 g. The formulated suspension was composed of: Eudragit FS 30D®, triethyl citrate, magnesium stearate, titanium dioxide, talc, pink pigment and water. Scanning electron microscope images of the seeds before and after coating were analyzed. Adsorption isotherms at 25 ºC were determined for the coated and in nature seeds using the dynamic method. The results were adjusted using five models of sorption isotherms: GAB, Caurie, Oswin, Peleg and Smith. For the seeds in nature, the best fit was obtained with the model of Peleg (R² = 0.998), whereas for the coated seeds the best fit was obtained with the model of Smith (R² = 0.981). During the storage, three groups of seeds were analyzed: the group of the coated seeds; the group of the seeds in nature (that were sown with the tegument dormancy) and, finally, the group of scarified seeds, which corresponds to the seeds that were stored in nature, but, dormancy was broken before sowing. During the 380 days of storage germination tests, accelerated aging and moisture content were performed at intervals of approximately 40 days. For the period analyzed, the fresh seeds had average moisture content equal to 9.25 %, while for the coated seeds, the average was 7.12 %. At the end of storage, the germination of scarified seeds and of coated seeds showed no statistical difference. For the accelerated aging test, the scarified seeds were more vigorous compared to the coated seeds. The percentages of germination and the vigor of the seeds sown in nature were lower than the other groups, because the tegument dormancy impeded the absorption of water, an essential component for the seed to germinate / Doutorado / Engenharia de Processos / Doutor em Engenharia Química
33

Desempenho em laboratório e em campo de sementes de milho submetidas a diferentes tempos de envelhecimento /

Nogueira, Débora Cristiane. January 2011 (has links)
Orientador: Marco Eustaquio de Sa / Banca: João Antonio da Costa Andrade / Banca: Kuniko Iwamoto Haga / Banca: Gisele Herbst Vazquez / Banca: Neli Cristina Belmiro dos Santos / Resumo: O uso de sementes com alto nível de vigor é fundamental para o sucesso de um empreendimento agrícola, pois apresentam melhor desempenho em campo, resultando em maior produção. O objetivo do trabalho foi verificar o nível do vigor em sementes de três híbridos de milho submetidas ao envelhecimento acelerado e seus desempenhos em laboratório e em campo. Para tanto sementes dos híbridos AG-5020, AG-8088 e BG-7049 foram envelhecidas artificialmente à 41oC por 0, 48 e 72 horas e secadas em estufa à 38 °C/48 horas para a formação dos diferentes lotes. Experimento 1 - No laboratório, verificou-se o nível de vigor e o desempenho das sementes dos diferentes lotes por meio de análises de germinação, primeira contagem, deterioração controlada, tetrazólio, comprimento de raiz primária e mesocótilo, número de raízes/plântula, massa de matéria seca de plântula e emergência em solo. Experimento 2 - No campo as sementes foram semeadas manualmente em parcelas de 8 linhas de 5m, espaçamento de 0,5m e densidade de 80.000 plantas ha-1. Verificou-se o nível de vigor e o desempenho das plantas em campo pelas avaliações de características morfológicas das plantas, caracteres da espiga e componentes de produtividade. O delineamento experimental foi o inteiramente casualizado com os tratamentos obtidos da combinação 3 x 3 (híbridos x níveis de vigor) com quatro repetições. Em laboratório as sementes mais vigorosas apresentaram melhores desempenhos e em campo proporcionaram a obtenção de maior produtividade, o que se deve principalmente ao maior estande final obtido. As características das plantas e das espigas estão relacionadas ao genótipo de cada híbrido não se verificando efeito do vigor das sementes / Abstract: The use of seeds with high level of vigor is fundamental to the success of an agricultural development, since its have better performance in the field, resulting in increased production. The objective of this study was to assess the level of vigor in seeds of three maize hybrids submitted to accelerated aging and their performance in laboratory and field. Seeds of AG-5020, AG-8088 and BG-7049 were artificially aged at 41°C for 0, 48 and 72 hours and dried in an stove at 38 °C /48 hours for the formation of the different lots. Experiment 1 - in the laboratory, we found the level of vigor and the performance of different seed lots by means of analysis of germination, first count, controlled deterioration, tetrazolium, length of primary root and mesocotyl, number of roots/seedling, seedling mass dry matter and seedling emergence in soil. Experiment -2 the seeds were manually sown in plots of 8 rows of 5m, 0,5 m spacing and density of 80000 plants ha-1. The level of vigor and performance of plants in the field evaluations of morphological characteristics of plants, components and characters of the spike in productivity. The experimental design was completely randomized treatments obtained with the combination 3 x 3 (hybrid x vigor levels) with four replications. In the laboratory the most vigorous seeds showed better performances and the field higher productivity, which is mainly due to higher final stand. As characteristics of plants and spike are related to the genotype of each hybrid was not observed effect of vigor seeds / Doutor
34

Seed treatment of maize, sorghum and sunflower with effective micro- organisms

Van Tonder, Nicolaas Christiaan Petrus January 2012 (has links)
Thesis (M. Tech. Agriculture) -- Central University of Technology, Free state, 2012 / A series of incubation studies and greenhouse experiments were conducted to evaluate the use of EM seed treatments, at different application levels, handling techniques and soil conditions on germination and seedling vigour of selected cultivars of maize, sorghum and sunflower. Two incubation studies were conducted to evaluate the germination and seedling vigour of maize, sorghum and sunflower seeds treated with M-EM from three different suppliers, multiplied at two different ratios (1% and 3%) and diluted at three different levels (0.01%, 0.1% and 1.0%) compared to a control treated with pure water. Results revealed no significant differences under optimum germination conditions, while seedlings under cold stress indicated that M-EM treatments positively affected germination and seedling vigour compared to the control treatments. Two incubation studies were also conducted to evaluate the germination and seedling vigour of maize, sorghum and sunflower seeds treated with M-EM from three different suppliers, multiplied at two different ratios (1% and 3%) and exposed to the influences of irradiation and temperature fluctuation. From the results became clear that the correct storage and handling is essential in optimizing the effect of M-EM on seeds. Even though M-EM was exposed to irradiation and temperature fluctuation, M-EM still had positive effects on germination and seedling vigour. Pot experiments were conducted to determine the effect of EM as seed treatment, at different dilutions, on germination, seedling vigour and dry mass of maize, sorghum and sunflower at different planted depths. Germination were not affected by the M-EM treatment, while shoot length results indicated that seed treated with M-EM could have significant effect on seedling survival. A greater effect was visible on the shoot length of shallow planted seeds, than on deeper planted seeds. From the results no single company, ratio or dilution could be prescribed as paramount. To further investigate the effect of M-EM subjected to the influences of irradiation and temperature fluctuation; maize, sorghum and sunflower seeds were treated with M-EM from three different suppliers, multiplied at two different ratios (1% and 3%) and exposed to the influences of irradiation and temperature fluctuation and planted in soil. M-EM treatments only benefited the germination of deeper planted sorghum seeds compared to the control treatments. The shoot lengths of deeper planted maize and sunflower seed were positively increased by the M-EM treatments while also resulting in significant results for the overall shoot length of sorghum. The third pot study was conducted to determine the influence of EM as a seed treatment on maize, sorghum and sunflower planted in three different soils, namely: sterilized soil, soil treated with M-EM and Fusarium containing soil. Germination and seedling vigour results of the sterilized and M-EM treated soil revealed to be superior to that of the Fusarium containing soil. From the results was concluded that M-EM treatments will probably improve early seedling growth of maize, sorghum and sunflower compared to untreated seed and that M-EM seed treatment and a pre-plant EM soil treatment might assist seeds in unfavourable germination and growth conditions.
35

Phytate related response of maize seed to phosphorus and temperature.

Asanzi, Nafabuanga Mireille. January 2006 (has links)
The aim of the study was to determine the effect of day/night temperatures (22/l6°C, 2712l oC and 33/27°C) and phosphorus levels (0, 0.12 and 1.2g per 20 kg soil) on seedling establishment and seed viability during three stages of seed development (15, 22 and 33 days after flowering) for seed of normal and quality protein maize cultivars. Soluble carbohydrate accumulation and mineral element content were determined using environmental scanning electron microscopy (ESEM) in relation to seed phytate levels and seed germination capacity at different stages of development. Leaf emergence rate and plant height during seed development were significantly (P < 0.05) influenced by temperature and phosphorus nutrition. Phosphorus in seed is stored primarily in the form of phytic acid, also known as phytate. Accumulation of phytate takes place during maturation phase of seed development. Phosphorus nutrition and temperature also caused a.significant (P < 0.05) increase in seed germination at all stages of seed development. Furthermore, phosphorus nutrition and temperature influenced occurrence of soluble carbohydrates in seeds. Myo-inositol, the sugar alcohol that forms the basic structure of phytate, was increased by P nutrition and increasing growth temperature. Whereas, QPM maize was generally found to perform poorly than normal maize, with respect to phytate content, seed germination and seedling establishment, both cultivars displayed the same responses to phosphorus nutrition and temperature. In both cultivars, globoids, the sites of phytate synthesis and storage, were found only in the embryonic axis. Subsequently, there were significantly low levels of mineral elements (P, Mg and K) found in the endosperm, compared with embryonic axis. This finding suggested that the embryonic axis plays a major role in seed performance, through its effects emanating from phyate metabolism. Myo-inositol plays a role in membrane biogenesis during stress conditions such as temperature by maintaining the integrity of the cell wall and minimizes the leaching of cations essential during germination. Myo-inositol, although it occurs in small concentrations, could be used to indicate seed quality in maize, because its accumulation was found to be associated with enhanced phyate levels and better seed germination in a wide range of temperatures. Low vigour seeds are associated with high electrolyte leakage during imbibition. Mineral elements form a significant portion of the imbibition leachate, which causes seeds to lose nutrients for early seedling growth. This study provided evidence that phosphorus nutrition can alleviate poor seed vigour of maize by improving phytate levels. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.
36

Pepper and tomato seed performance in response to imbibition and dehydration.

Nemakanga, Rendani. January 2005 (has links)
The International Seed Testing Association and the Association of Official Seed analysts define seed vigour as the ability of a seed lot to perform during the germination process and crop stand establishment under a wide range of environmental conditions. There are many ways to determine seed vigour, but few satisfy the requirements of being simple, inexpensive and reproducible, among others, to permit the seed industry to adopt seed vigour as an indicator of seed quality when they sell seeds. Hence, the standard germination test, which is performed under uniform and favourable conditions, is generally used to indicate seed quality when seeds are marketed. The objective of this study was to determine the performance of tomato and pepper seeds in response to pre-germination hydration and dehydration relative humidities (12%, 49% and 75% RH). Before hydration, seeds were hydrated at three temperatures (10°C, 20°C and 30°C). Hydration was performed by imbibing pre-weighed pepper ('Santarini' and 'California Wonder'), Chilli and tomato ('Heinz', 'Marondera' and 'Roma') seeds for 2 h in 10 ml of distilled H(2)0 per 100 seeds at 10°C, 20°C and 30°C. Dehydration was performed by change in seed mass determined during a 72-hour dehydration at 12%, 49% and 75% RH. Seed performance in response to imbibition and dehydration was determined by leakage of electrolytes from seeds during imbibition, laboratory germination capacity and seedling emergence under simulated shadehouse nursery conditions. A pot experiment was conducted to determine the effects of seed treatments on yield. Seed mass increased by about 50% during the 2-hour of hydration. Dehydration was hastened by decreasing the RH, and 12% RH significantly (P < 0.05) reduced the post-imbibition seed moisture content compared with 49% and 75% RH. The latter two relative humidities reduced the seed moisture content to about 10% and 15%, respectively, for all cultivars, irrespective of imbibition temperature. Low imbibition temperature (10°C) significantly (P < 0.01) increased electrolyte leakage, compared with high imbibition temperatures (20°C and 30°C), which were not significantly different from each other. At all hydration temperatures, low RH (12%) caused a significant (P < 0.01) decrease in seed germination whereas 49% RH and 75% RH apparently had a priming effect on seeds. There was no significant difference between imbibition temperatures, with respect to seed germination, but 100G caused a significant decrease in germination index, a measure of seed vigour. Seedling emergence was significantly (P < 0.01) reduced by both low imbibition temperature (10oG) and low dehydration relative humidity (12% RH). The negative effects of low imbibition temperature and rapid dehydration at 12% RH were also observed as stunted seedling growth. Principal component analysis and linear regression were used to determine a statistical model to predict seedling emergence from germination percentage. The model predicted emergence consistently, but it overestimated it by about 2% to 3%. It is concluded that low imbibition temperature and rapid dehydration can be used to simulate stress to determine seed performance in pepper and tomato. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.
37

Ecosystem Recovery in Estuarine Wetlands of the Columbia River Estuary

Kidd, Sarah Ann 08 June 2017 (has links)
In the restoration of tidal wetland ecosystems, potential drivers of plant community development range from biotic controls (e.g. plant competition, seed dispersal) to abiotic controls (e.g. tidal flooding, salinity levels). How these controls influence the success of tidal wetland restoration are only partly understood, but have important implications for wetland habitat recovery. Specifically, the extent to which the existing native and non-native seed banks in tidally reconnected wetlands interact with these controls is not clear, yet the potential success of passive restoration methods depends upon this understanding. For a 54-year chronosequence of eleven tidal wetland restoration sites in the Lower Columbia River of western Oregon, USA, it was hypothesized that native plant species and soil properties would show trends approaching reference levels within 3 to 20 years post-restoration and that lower elevation wetland areas within restored sites would exhibit a greater native species abundance and similarity to reference sites, compared with restored high elevation wetland areas. Results indicated that plant species richness, soil organic matter, bulk density, pH, and salinity conditions among the restoration sites reached reference wetland ranges within 3-6 years post-tidal reconnection. The mid-low marsh elevation zones (<2.5 m) recovered native plant cover within 3-6 years post-tidal reconnection, while high marsh elevation zones (>2.5 m) remained dominated by nonnative species Phalaris arundinacea and Juncus effusus subsp. effusus. To investigate the mechanisms driving these non-native plant invasions, it was ii hypothesized that native and non-native wetland plant community distributions would be reflective both of their abundance in the seed bank and of their germination tolerance to wetland tidal flooding and salinity conditions. Using a factorial study design of three tidal conditions by three salinity levels, these hypotheses were tested in the greenhouse. Overall, non-native seeds were found to significantly outnumber native seeds in both seed banks. In the greenhouse, P. arundinacea and J. effusus were found to germinate more readily out of the seed bank under freshwater high-marsh flooding (1 hour a day) treatments as compared to oligohaline (3 ppt) mid-low marsh flooding (3-6 hours twice a day) treatments and to brackish salinity (10 ppt) treatments. Dominant native wetland species, Carex lyngbyei and Schoenoplectus lacustris, germination were not found to vary significantly among the treatments (p > 0.10). These results indicate that the salinity and flooding gradients within these restored marshes suppress germination of the non-native species in the low-mid marsh but not in the high marsh, where they are likely able to outcompete the native species due to their dominance in the seed bank. The implications of these results for passive tidal wetland restoration efforts are that both seed bank composition and species-specific tolerances to restored tidal flooding and salinity gradients are key mechanisms driving native and nonnative plant community development and resilience.
38

Desempenho agronômico de cultivares de amendoim no Paraná para rendimento de grãos, teor de óleo e qualidade fisiológica de sementes / Performance of peanut cultivars in Paraná state for grain yield, oil content and physiological quality of seeds

Ribeiro, Gidiane Prado 13 November 2013 (has links)
Made available in DSpace on 2017-07-10T17:59:28Z (GMT). No. of bitstreams: 1 Gidiane Prado Ribeiro.pdf: 2064482 bytes, checksum: a59261eef67a684d39f1d7d22b3eeaeb (MD5) Previous issue date: 2013-11-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The peanut (Arachis hypogaea L.) is an oilseed. The seed of peanut butter has about 50% oil content. This crop has great potential as a feedstock for the biodiesel program implemented by the Brazilian government. The aim of this study was to investigate the agronomic performance of 12 peanut cultivars in 18 environments in the Paraná State. Another objective was to study the conditions that may influence the physiological quality of seeds produced and stored by the farmers themselves, by multifactor test with five factors: cultivars (IAC 886 and IAC Runner Tatu ST), locations, (Irati, Londrina and Santa Tereza do Oeste), packaging (paper bag, plastic bag and PET bottle), environments (cold chamber and ambient temperature) and time stored period. It was concluded that there were significant effects for cultivars, environments (years, seasons and locations) and the genotype x environment interaction for shelled grain yield and oil content in peanut seeds. The cultivars IAC Tatuí, IAC Tupã and BRS Havana showed high yield. High oil content was verified in the cultivars BRS 151-L7, IAC Tatuí and BRS Havana. The adaptability analysis for grain yield showed the following results: the cultivars Runner IAC 886 and IAC Caiapó showed specific adaptation to unfavorable environments, while IAPAR 25 Tição and IAC Tupã favorable. The cultivar IAC Tatu ST was more stable for grain yield. The physiological quality of peanut seeds is influenced by cultivars, locations, environments and time stored period. Physiological statistically superior quality was observed in the cultivar IAC Tatu ST, seeds produced in Londrina, the environment cold chamber and the second period seeds storage. The packaging used (paper bag, plastic bag and PET bottle) didn t influence the seeds viability, however the PET bottles showed up handling more practical and agile. / O amendoim (Arachis hypogaea L.) é uma oleaginosa, com teor de óleo de cerca de 50% em suas sementes, sendo considerada uma cultura energética. O objetivo deste estudo foi investigar o desempenho agronômico de 12 cultivares de amendoim, em 18 ambientes no estado do Paraná. Outro objetivo foi estudar as condições que podem influenciar na qualidade fisiológica das sementes produzidas e armazenadas pelos próprios agricultores, mediante ensaio multifatorial com cinco fatores: cultivares (IAC 886 e IAC Tatu ST) Runner, locais, (Irati, Londrina e Santa Tereza do Oeste), embalagem (saco de papel, saco de plástico e garrafa PET), ambientes (câmara fria e temperatura ambiente) e período de armazenamento. Concluiu-se que houve efeito significativo para cultivares, locais e para a interação cultivares x locais para as características rendimento de grãos sem casca e teor de óleo nas sementes. As cultivares que se destacaram em rendimento de grãos foram IAC Tatuí, IAC Tupã e BRS Havana. Para teor de óleo foram BRS 151-L7, IAC Tatuí e BRS Havana, portanto em ambos os aspectos sobressaíram IAC Tatuí e BRS Havana. A análise de adaptabilidade para rendimento de grãos apresentou os seguintes resultados: as cultivares Runner IAC 886 e IAC Caiapó presentaram adaptação específica a ambientes desfavoráveis, enquanto que IAPAR 25 Tição e IAC Tupã aos favoráveis. Em termos de estabilidade para rendimento de grãos a cultivar IAC Tatu ST foi a mais previsível. A qualidade fisiológica das sementes de amendoim é influenciada pelas cultivares, locais, ambientes e período de tempo em que foram armazenadas. A cultivar IAC Tatu ST apresentou qualidade fisiológica estatisticamente superior, assim como o local Londrina, o ambiente de câmara fria e o segundo mês de período de armazenamento das sementes. As embalagens utilizadas (saco de papel, saco de plástico e garrafa PET) não influenciaram na viabilidade das sementes, no entanto as garrafas PET mostraram-se de manuseio mais prático e ágil.

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