Typecript Includes bibliographical references

No abstract available. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.

Biochemical and ultrastructural changes associated with chilling injury (CI) in soybean seeds imbibed at 5°C and 25°C were investigated. Soybean seed germination appeared to be affected by chilling temperatures and initial seed moisture content. Seeds with higher moisture contents exhibited 85% germination, while low moisture content seeds had a 32% germination. Leakage rates were greater in chilled seeds, indicating that membrane integrity in the tissues was impaired at chilling. The low rates of potassium ion leakage between 6 and 24 hours of imbibition compared to the high peroxide levels observed during this period led to the suggestion that lipid peroxidation was a better marker of CI than leakage. Transient changes in lipid hydroperoxide levels were observed in chilled and non-chilled seeds and axes. However, in axes, the increase in lipid hydroperoxides after 12 hours of imbibition at chilling temperatures was associated with an 18% decline in linoleic acid levels of total lipid fraction. Similarly, a 10% decline was observed in the polar lipid fraction. These results suggest that the capacity of seeds to control lipid peroxidation may be an important component in CI and that a consequence of peroxidation is likely to be a loss of fatty acid unsaturation. Sugar levels were not affected by chilling and non-chilling temperatures and no relationship could be established with CI. Antioxidant defense enzymes (catalase and superoxide dismutase) were expressed at chilling and non-chilling temperatures and increases were observed after 24 hours of imbibition which showed an apparent correlation with increases to lipid hydroperoxide levels. Enzyme levels decreased after 48 hours of imbibition at a time which coincided with the decline observed in the peroxide levels. Overall, no marked differences were observed in chilled and non-chilled cells at the ultrastructural level, except that vacuolar reserve mobilization was markedly impeded. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1996.

Orientador: Cibele Chalita Martins / Coorientadora: Edna Ursulino Alves / Banca: Letícia Ane Sizuki Nociti Dezem / Banca: Silvelena Vanzolini Segato / Banca: Rita de Cássia Panizzi / Banca: Rinaldo Cesar de Paula / Resumo: Dentro de um programa de controle de qualidade, a avaliação da sanidade e do vigor das sementes é necessária para o sucesso da produção. Assim, o trabalho foi conduzido com o objetivo de identificar os fungos e verificar a eficiência de testes de vigor na diferenciação da qualidade dos lotes de sementes de Brachiaria brizantha cv. Marandú e Xaraés, visando obter informações sobre a qualidade sanitária das sementes e a emergência de plântulas em campo. Vinte lotes de sementes produzidas nos Estados de Mato Grosso do Sul, Mato Grosso, Goiás, Minas Gerais, São Paulo e Bahia foram submetidos à avaliação do teor de água, germinação e microflora fúngica, realizada pelo método do papel de filtro (blotter-test). Para avaliar o vigor e potencial fisiológico foram utilizados dezessete lotes de sementes, sendo oito da cultivar Marandú e nove da Xaraés, avaliados quanto ao teor de água, testes de germinação e vigor (primeira contagem de germinação, condutividade elétrica, emergência de plântulas, primeira contagem e índice de velocidade de emergência de plântulas em areia no laboratório e emergência de plântulas em campo). A microflora fúngica diagnosticada em sementes comerciais de capim marandú e xaraés é constituída por Helminthosporium sp., Fusarium sp., Phoma sp., Curvularia sp., Pyricularia grisea, Chaetomium sp., Nigrospora sp., Colletotrichum sp. e Aspergillus sp. não afeta a germinação de sementes de capim-marandú, no entanto, a incidência de Fusarium sp. e Aspergillus sp. reduz... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Within a quality control program, the evaluation of health and seeds vigor are fundamental and necessary for the successful production. Thus, this study was conducted in order to identify fungi and verify the efficiency of vigor tests in the quality differentiating of Brachiaria brizantha cv., Marandu and Xaraes seed lots, in order to obtain information that improve the sanitary quality of seeds and seedling emergence in the field. Twenty seed lots produced in the states of Mato Grosso do Sul, Mato Grosso, Goias, Minas Gerais, Sao Paulo and Bahia were evaluated for water content, germination and fungal microflora by the filter paper method (blotter-test). To evaluate the vigor and potential physiological were used seventeen seed lots, eight of the cultivar Marandu and nine of the Xaraes submitted to the germination test, first counting of germination test, electrical conductivity, seedling emergence, first germination count and seedling emergence speed index in the sand performed in the laboratory and emergency seedling tests in the field. The fungal microflora diagnosed in commercial seed lots of marandu and xaraes grasses consists of Helminthosporium sp., Fusarium sp., Phoma sp., Curvularia sp., Pyricularia grisea, Chaetomium sp., Nigrospora sp., Colletotrichum sp. and Aspergillus sp.. germination of marandu grass seeds was not affected by the incidence of fungi. The incidence of Fusarium sp. and Aspergillus sp reduces the germination of xaraes Regarding producing locations... (Complete abstract click electronic access below) / Doutor

A utilização de procedimentos rápidos e confiáveis para análise de sementes é fundamental para a tomada de decisões nas diferentes etapas do processo produtivo e definição do destino dos lotes de sementes. Neste sentido, os objetivos desta pesquisa foram: a) avaliar a estrutura de sementes de crotalária, utilizando raios X para avaliação das partes da semente, identificação de possíveis danos causados por injúrias mecânicas, por percevejo e tecidos deteriorados nas sementes e sua relação com a germinação; b) verificar a possibilidade de utilização do sistema computadorizado de análise de plântulas (SVIS®) para detectar diferenças de vigor entre lotes de sementes de Crotalaria juncea, em comparação com as informações fornecidas por testes tradicionalmente utilizados para a espécie. Foram utilizadas seis lotes de sementes de crotalária do cultivar IAC-KR1, tanto para avaliação da estrutura de sementes quanto para a análise de imagens de plântulas. As análises relativas à morfologia interna das sementes foram realizadas em apenas uma época, no início da pesquisa, ao passo que aquelas relativas ao sistema computadorizado de imagens de plântulas e demais testes de vigor foram realizados em duas épocas, espaçadas de quatro meses. Inicialmente as sementes foram submetidas ao teste de raios X e ao teste de germinação. As plântulas normais, anormais e sementes mortas foram fotografadas e analisadas paralelamente às imagens radiográficas das sementes. Na segunda etapa da pesquisa, os seis lotes foram submetidos a testes de germinação e de vigor (primeira contagem de germinação, envelhecimento acelerado, emergência de plântulas em areia e condutividade elétrica). Para determinação do vigor das sementes por meio do SVIS®, as plântulas foram avaliadas aos três e quatro dias após a semeadura do teste de germinação, sendo obtidos dados referentes ao índice de uniformidade de desenvolvimento, vigor e comprimento de plântulas. Concluiu-se que a análise de imagens de raios X permite identificar danos mecânicos, por percevejo e tecidos deteriorados em sementes de crotalária e relacioná-las com a germinação; o SVIS® é uma alternativa viável para a avaliação do vigor de sementes de crotalária. / Fast and reliable procedures for analyzing seeds are fundamental for taking decisions during the different production stages and defining the destination of seed lots. Therefore, the objectives of this study were: a) to study the structure of sun hemp seeds with X-ray to evaluate the seed parts and identify possible damage caused by mechanical injuries, stink bugs and deteriorated tissues and their relation to germination; b) verify the possibility of using a computerized seedling analysis system (SVIS®) to detect differences in vigor between seed lots of Crotalaria juncea, and compare the results with those obtained from vigor tests used for the species. Six lots of the sun hemp cultivar IAC-KR1 were used to evaluate seed structure and also to analyze seedling images. The internal morphology seed was analyzed only at the beginning of the study whereas the computer analysis of seedling images and the other vigor tests were done at two different times, four months apart. The seeds were first submitted to X-ray and germination tests. Normal and abnormal seedlings and dead seeds were photographed and analyzed at the same time as the seed X-ray images. In the second stage of the study, the six lots were submitted to germination and vigor (first germination count, accelerated aging, seedling emergence in sand and electrical conductivity) tests. To determine the seed vigor using the SVIS®, the seedlings were evaluated three and four days after sowing for the germination test, when data on the uniformity development index, vigor and seedling length were obtained. It was concluded that the analysis of X-ray images is efficient for identifying mechanical damage, stink bug damage and deteriorated tissues and allowed to establish an association between their occurrence and germination; the SVIS® is a viable alternative for evaluating the vigor of sun hemp seeds.

A utilização de procedimentos rápidos e confiáveis para análise de sementes é fundamental para a tomada de decisões nas diferentes etapas do processo produtivo e definição do destino dos lotes de sementes. Neste sentido, os objetivos desta pesquisa foram: a) avaliar a estrutura de sementes de crotalária, utilizando raios X para avaliação das partes da semente, identificação de possíveis danos causados por injúrias mecânicas, por percevejo e tecidos deteriorados nas sementes e sua relação com a germinação; b) verificar a possibilidade de utilização do sistema computadorizado de análise de plântulas (SVIS®) para detectar diferenças de vigor entre lotes de sementes de Crotalaria juncea, em comparação com as informações fornecidas por testes tradicionalmente utilizados para a espécie. Foram utilizadas seis lotes de sementes de crotalária do cultivar IAC-KR1, tanto para avaliação da estrutura de sementes quanto para a análise de imagens de plântulas. As análises relativas à morfologia interna das sementes foram realizadas em apenas uma época, no início da pesquisa, ao passo que aquelas relativas ao sistema computadorizado de imagens de plântulas e demais testes de vigor foram realizados em duas épocas, espaçadas de quatro meses. Inicialmente as sementes foram submetidas ao teste de raios X e ao teste de germinação. As plântulas normais, anormais e sementes mortas foram fotografadas e analisadas paralelamente às imagens radiográficas das sementes. Na segunda etapa da pesquisa, os seis lotes foram submetidos a testes de germinação e de vigor (primeira contagem de germinação, envelhecimento acelerado, emergência de plântulas em areia e condutividade elétrica). Para determinação do vigor das sementes por meio do SVIS®, as plântulas foram avaliadas aos três e quatro dias após a semeadura do teste de germinação, sendo obtidos dados referentes ao índice de uniformidade de desenvolvimento, vigor e comprimento de plântulas. Concluiu-se que a análise de imagens de raios X permite identificar danos mecânicos, por percevejo e tecidos deteriorados em sementes de crotalária e relacioná-las com a germinação; o SVIS® é uma alternativa viável para a avaliação do vigor de sementes de crotalária. / Fast and reliable procedures for analyzing seeds are fundamental for taking decisions during the different production stages and defining the destination of seed lots. Therefore, the objectives of this study were: a) to study the structure of sun hemp seeds with X-ray to evaluate the seed parts and identify possible damage caused by mechanical injuries, stink bugs and deteriorated tissues and their relation to germination; b) verify the possibility of using a computerized seedling analysis system (SVIS®) to detect differences in vigor between seed lots of Crotalaria juncea, and compare the results with those obtained from vigor tests used for the species. Six lots of the sun hemp cultivar IAC-KR1 were used to evaluate seed structure and also to analyze seedling images. The internal morphology seed was analyzed only at the beginning of the study whereas the computer analysis of seedling images and the other vigor tests were done at two different times, four months apart. The seeds were first submitted to X-ray and germination tests. Normal and abnormal seedlings and dead seeds were photographed and analyzed at the same time as the seed X-ray images. In the second stage of the study, the six lots were submitted to germination and vigor (first germination count, accelerated aging, seedling emergence in sand and electrical conductivity) tests. To determine the seed vigor using the SVIS®, the seedlings were evaluated three and four days after sowing for the germination test, when data on the uniformity development index, vigor and seedling length were obtained. It was concluded that the analysis of X-ray images is efficient for identifying mechanical damage, stink bug damage and deteriorated tissues and allowed to establish an association between their occurrence and germination; the SVIS® is a viable alternative for evaluating the vigor of sun hemp seeds.

In recent years research has shown that exposing seed to smoke or smoke solutions results in increased germination of some, but not all the species tested. Tests showed that exposing seeds of some commercial crops to smoke increased early plant growth. The stimulatory effects of smoke were shown to benefit the germination of species regardless of whether or not fire played a part of the species ecological cycle. In commercial forest nurseries any method of increasing the recovery rate of seed presents opportunities for realising savings of related production costs. Greater recovery rates of genetically improved seed present opportunities for capturing more related growth in field operations. Improving efficiencies of seed recovery at an early point in the production chain have multiplied effects further on down the chain. Two species of pine, namely Pinus taeda and Pinus elliottii that do not generally present high rates of germination were selected to test if applications of smoke solution could increase germination or emergence rates by more than 5%. As seed of both species are known to respond positively to existing seed pre-treatments the effects of smoke needed to be tested in combination, and apart from the pre-treatments. A secondary aim of the study was to examine the effect of smoke on early plant growth. Attempts to optimizes the concentration of the smoke solution were not undertaken as part of this study, as a rinsing treatment, included in the trials, is known to remove any inhibitory effects of a high concentration of the smoke solution. Tests to determine the variability of the seedlots was carried out for statistical purposes. The interaction between smoke application and pre-treatments were tested, firstly in Petri dishes under controlled environmental conditions, and then in nursery trays under standard commercial nursery conditions for both species. The inclusion of smoke in combination with the target moisture stratification (TMS and rinse pre treatment) had a significantly positive effect on P. taeda in a controlled environment. The same combination did not yield a positive results when tested under nursery conditions. Recommendations are made regarding future tests to see if the beneficial combination found in the controlled environment could be replicated under nursery conditions. Further motivation for conducting the tests exists in that the particular combination set gave significantly better early plant growth under nursery conditions. No other combinations tested yielded positive results. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.

Transverse cotyledonal cracking (TVC) was characterised at physiological, biochemical and molecular levels in three common bean (Phaseolus vulgaris L.) cultivars: Imbali, Tongaat and Tokai. The incidence of TVC was determined visually on ten-day old seedlings and was expressed as the number of cracks per plant. The effect of Ca++ on TVC incidence was examined by enhancing the calcium content of seed cotyledons using calcium salts in seed priming and coating. EDAX was used to quantify the cotyledonal calcium content. Activities of the pectinolytic enzymes polygalacturonase (PG) and pectin methylesterase (PME) were assayed at dry seed, VC, R4 and R6 phenophases of the bean plant, and zymogram electrophoresis was used to identify the two enzymes. The results showed that cultivars Imbali, Tongaat, and Tokai were susceptible resistant and intermediate, respectively, with respect to TVC incidence. Calcium uptake was higher in Tongaat cultivar (P= 0.05) compared with Imbali and Tokai, irrespective of calcium salt enhancement. Vigour was significantly reduced (P< 0.01) by both coating and priming. TVC significantly lowered yield (P= 0.05) in the susceptible Imbali cultivar. Zymogram analysis identified lytic bands at ~45kDa (PG gel) and ~30kDa (PME gel). The activity profile of PME was similar for all cultivars. However, PG activity of susceptible Imbali was high in dry seeds and at the R4 and R6 stages of plant development, whereas the more resistant cultivars displayed high activity at the VC stage only. It is concluded that high PG activity at R4 stage is a more reliable determinant of green bean propensity to cotyledonal cracking. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

Orientadores: João Domingos Biagi, Claudio José Barbedo / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-19T22:55:33Z (GMT). No. of bitstreams: 1 Parisi_JoaoJoseDias_D.pdf: 700508 bytes, checksum: 9956b2ce3f085d143589b761f27c7d01 (MD5) Previous issue date: 2012 / Resumo: O elevado metabolismo dificulta a manutenção da viabilidade de sementes de Inga vera. As principais estratégias para a conservação dessas sementes durante o armazenamento consistem na desidratação parcial, na adição de ácido abscísico, no uso de solução de polietileno glicol e de baixas temperaturas. Contudo, tais condições ainda podem conduzir à deterioração, tanto pela atividade do seu próprio metabolismo, como pelo desenvolvimento de micro-organismos favorecidos pela umidade. Desta forma, o presente trabalho teve como objetivo analisar o grau de interferência dos fungos no metabolismo respiratório dos embriões de Inga vera com diferentes níveis de hidratação e a eficiência do tratamento com fungicidas, visando à manutenção da viabilidade durante o armazenamento. Para tanto, os embriões foram obtidos em três anos, sendo em 2009 colhidos em duas fases distintas de maturação (imaturos e maduros), submetidos a dois níveis de secagem, tratados ou não com carboxin + thiram e armazenados sob 7 e 25 oC por até 65 dias. Em 2010, foram colhidos maduros, submetidos a quatro níveis de secagem, tratados ou não com carbendazin + thiram e armazenados a 7 ºC por 120 dias. Nos experimentos de avaliação da respiração, os embriões obtidos em 2010 foram tratados ou não com carbendazin + thiram, mortos ou não por congelamento e inoculados ou não com Aspergillus flavus. Os colhidos em 2011 foram mantidos sem secagem e tratados ou não com carbendazin + thiram e a respiração foi avaliada a 7 e a 25 ºC. Constatou-se que a incidência de fungos, principalmente Fusarium oxysporum, juntamente com o teor de água e a temperatura influenciam nas taxas respiratórias dos embriões de I. vera maduros e que o tratamento com carbendazin + thiram, na dose de 80 mL do produto comercial para 100 kg de embriões, é eficiente na manutenção da viabilidade de embriões maduros e sem secagem, a 7 ºC por 120 dias. Pestalotiopis sp., Phoma sp., Phomopsis diachenii e Colletotrichum gloeosporioides aparecem durante o armazenamento, simultaneamente à deterioração dos embriões de I. vera. O desenvolvimento de fungos em embriões de I. vera difere do padrão clássico definido com base em sementes ortodoxas / Abstract: The high metabolism hinders the maintenance of Inga vera seeds viability. The main strategies for the conservation of these seeds during storage consist of the partial dehydration, addition of abscisic acid, use of polietileno glicol solution and of low temperatures. However, such storage conditions can lead to further deterioration of the seed, either by the activity of its own metabolism, as the development of microorganisms favored by moisture. This study aimed to analyze the degree of interference of fungi on the respiratory metabolism of Inga vera embryos with different levels of hydration and the efficiency of fungicide treatment, as maintaining these embryos viability during storage. The embryos were obtained in three years. In 2009 they were collected in two distinct stages of maturation (immature and mature), subjected to two drying levels, treated or not treated with carboxin + thiram and stored at 7 and 25 º C for up to 65 days. In 2010 the embryos were collected mature, subjected to four drying levels, treated or not treated with carbendazin + thiram and stored at 7 º C for 120 days. In the experiments carried out to evaluate the respiration, the embryos obtained in 2010, were treated or not treated with carbendazin + thiram, killed or not by freezing and inoculated or not with Aspergillus flavus. The embryos collected in 2011 were kept without drying, treated or not treated with carbendazin + thiram and respiration was evaluated at 7 and 25 ° C. It was found that the incidence of fungi, primarily Fusarium oxysporum, together with the water content and temperature influence respiration rates of mature embryos of I. vera and that the treatment with carbendazin + thiram at the dose of 80 mL of the commercial product to 100 kg of embryos is effective for maintaining the viability of mature embryos without drying at 7 ° C for 120 days. Pestalotiopis sp., Phoma sp., Phomopsis diachenii and Colletotrichum gloeosporioides are detected during the storage time, along with the deterioration of the embryos of I. vera. The development of fungi on embryos of I. vera differs from the classic pattern verified for orthodox seeds / Doutorado / Tecnologia Pós-Colheita / Doutor em Engenharia Agrícola

Cowpea (Vigna unguiculata. L) is an important African crop. However, it is also an underutilized grain legume. Consequently, there is not enough research data on cowpea seed physiology. Whereas there is evidence of cowpea being a drought tolerant crop, there is no evidence to associate plant drought tolerance with seed quality in response to water stress. This study sought to understand the effect of production site and water stress on cowpea seed quality development with respect to germination capacity and vigour. Patterns of raffinose family of oligosaccharides (RFO) during seed development to mature dry stage were used to physiologically relate seed performance to water stress. The effect of water stress and exogenous ABA on the accumulation of stress LEA proteins (dehydrins) in relation to seed quality development and germination was investigated. RFOs are known for their roles in desiccation sensitivity but no studies have shown their significance in cowpeas. Seeds of six cowpea cultivars were produced at two distinct growth sites characterised by irrigated and dry land conditions. The seeds were assessed during six developmental stages, for water content, dry matter accumulation, and performance. Harvested seeds were then planted in a pot experiment under controlled conditions to examine the effect of water stress on seed quality development and data collected during three developmental stages. Harvested seeds from the pot experiment were subsequently analyzed for changes in RFO accumulation during development using gas chromatography. The seeds were also used to investigate the effect of water stress and ABA on the accumulation of stress LEA proteins (dehydrins) in relation to seed quality development in cowpea. In addition, this study evaluated the use of image analysis as a method that can be used to objectively determine seed coat colour variation in cowpea. Statistical variation in individual seed’s solute leakage for cowpea cultivars differing in seed coat colour and produced under different environmental conditions was explored and correlations were done between seed conductivity test with other aspects of seed performance during germination. Furthermore the results of the conductivity test were compared with accelerated aging test, in relation to seed performance. The study provided evidence that cowpea seed lots produced under different environmental, and possibly management conditions may not differ with respect to seed quality as determined by germination capacity and vigour. However, significant differences between sites with respect to seed maturation patterns determined by water content and dry matter accumulation were observed. Adverse maternal environmental effects on the subsequent performance of seeds in a drought tolerant crop may not necessarily lead to poor performance. Cultivar differences in response to simulated drought conditions at the whole plant and tissue level can be considerable and highly variable; however, these differences may not have adverse effects on the germination and vigour of the seeds. Drought avoidance mechanisms at the whole plant level in cowpea are quite efficient in allowing the species to adapt to simulated drought conditions. These mechanisms may allow the cowpea cultivars to maintain metabolism and restore conditions for their continued growth under water stress; and produce few seeds of high germination capacity and vigour. Stachyose was found to be the predominant member of the raffinose family of oligosaccharides in cowpea. It is suggested that stachyose accumulation could be used as an indicator of stress tolerance in cowpea. However, the relationship between RFO concentration and the acquisition of desiccation remained as a matter of speculation in the present study and is still generally inconclusive. There was no evidence to suggest the acquisition of maximum desiccation tolerance is associated with maximum seed vigour. It is suggested in cowpea, which is drought tolerant, that maximum vigour does not necessarily imply the acquisition of maximum desiccation tolerance; rather there is a minimum level of desiccation tolerance that is required for the development of optimal seed vigour. The use of an in vivo approach in the study of LEA function in cowpea enabled the accurate comparison of two different groups of LEA proteins in developing cowpea seeds under conditions of water stress and in relation to germination and vigour. Both group 1 LEA and group 2 LEA (dehydrin) were shown to increase in concentration in response to water stress. In addition group 1 LEA protein was observed to be relatively abundant in cowpea seeds. A maternal influence on LEA protein gene expression under conditions of water stress, which may induce dehydrin accumulation vii during the earlier stages of seed development, was implied by the observation that dehydrin-like proteins were induced after two weeks of development in cowpea plants subjected to stress during the vegetative phase. In addition, the exogenous application of ABA delayed radicle protrusion; this was associated with a delay in the disappearance of LEA proteins and is suggestive of a relationship between LEA protein accumulation and the acquisition of desiccation tolerance. The study has demonstrated that image analysis can objectively discriminate seed coat colour variation in cowpea. Dark coloured seeds in general performed better than light coloured seeds; however seed coat colour was not always associated with better performance. A newly developed Aging Stress Differential Index (ASDI) has been used in this study to demonstrate a link between seed coat colour and sensitivity to water stress. The ASDI correlated well with the observations relating stress tolerance to stachyose accumulation. The skewed distribution patterns in individual electrical conductivity and the presence of extreme values may have implications with respect to the suitability of using standard statistical analyses which compare mean values to evaluate such data. In addition variation in individual electrical conductivity may also be influenced by cultivar differences and the chemical composition of the seed coat. Therefore associations between seed coat colour and electrical conductivity as a measure of performance should be treated with caution. The AA test does reflect changes in seed vigour, however ranked electrical conductivity values after AA did not consistently reflect differences in seed performance between cultivars and sites, and they did not correlate well with other aspects of performance. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.