• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 278
  • 94
  • 44
  • 18
  • 18
  • 18
  • 18
  • 18
  • 18
  • 7
  • 4
  • 2
  • 2
  • 2
  • 2
  • Tagged with
  • 515
  • 90
  • 70
  • 62
  • 46
  • 38
  • 37
  • 36
  • 34
  • 33
  • 30
  • 20
  • 20
  • 20
  • 19
  • 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.
401

Aplicação de silício em plantas de tomate cultivar micro-tom sob défice hídrico /

Corrêa, Carla Verônica, 1983. January 2019 (has links)
Orientador: Carmem Silvia Fernades Boaro / Banca: João Domingos Rodrigues / Banca: José Figueiredo Pedras / Banca: Veridiana Zocoler de Mendonça / Banca: Edvaldo Aparecido Amaral da Silva / Resumo: Há grande preocupação com a utilização e conservação dos recursos hídricos. Neste aspecto a agricultura apresenta destaque, devido ao expressivo consumo de água. Além disso, são preocupantes as alterações climáticas caracterizadas por veranicos que comprometem a produção agrícola. Desta forma, busca-se a utilização mais eficiente da água, seja por meio de plantas resistentes à seca, ou de seu cultivo em condições que aumentem a eficiência do uso de água pelas plantas. Assim, pesquisas estão sendo conduzidas com silício por se tratar de um elemento capaz de aumentar a resistência das plantas ao défice hídrico. No entanto, embora seja conhecido seu efeito benéfico ao reduzir os danos causados por défice hídrico em vegetais, não se conhecem os mecanismos fisiológicos, enzimáticos, gênicos, hormonais e estruturais relacionados com este elemento. Desta forma, o objetivo desta pesquisa foi verificar possíveis relações do silício com enzimas, genes e hormônios envolvidos na redução de danos causados por défice hídrico, além da sua deposição nos tecidos vegetais, interferindo na fisiologia do tomate cultivar Micro-Tom. Para isso, foram utilizadas seis concentrações de silício (0.00; 0.50; 1.00; 1.50; 2.00 e 2.50 g L-1 de Si) e três regimes hídricos (sem défice hídrico, com défice hídrico e com défice hídrico e reidratação). A aplicação de silício aumentou a taxa de transpiração, condutância estomática, taxa de assimilação de CO2, atividade calculada da Rubisco e eficiência do uso da ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract:There is great concern about water resources management, since agriculture stands out, due to it expressive consumption. Furthermore, climate change, as intense heatwave, affects agricultural productivity. Therefore, water use seems efficient either through plants resistance to drought or grown under well-developed water management. Lately, silicon studies are been conducted, since it increases plant resistance to water stress, but there is little information on physiological, enzymatic, genetic, hormonal and structural mechanisms related to silicon. Thus, this study aimed to verify possible relationships among silicon and enzymes, genes, hormones involved in the reduction of water stress damage; besides that, deposition in plant tissues that interferes in the species physiology.For this, six concentrations of silicon (0.00, 0.50, 1.00, 1.50, 2.00 and 2.50 g L-1 of Si) and three water regimes (without water deficit, water deficit and water deficit and rehydration). Results indicated that silicon application increased transpiration rate, stomatal conductance, CO2 assimilation rate, Rubisco activity and water use efficiency in water stressed plants and rehydrated at 1.00 g L-1 of Si. Also, maintained chlorophyll fluorescence by reducing dark fluorescence (Fd) and increasing dark maximum (FM), maximum quantum yield (Fv/FM), electron transport efficiency (ETE) and quantum yield (ɸPSII) in water stressed plants. The low Si concentration reduced the degradation of chlorophyll ain water stressed plants and increased activity of the enzymes superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), reducing lipid peroxidation. In general, the water stress impaired gas exchange, thus silicon application contributed to the maintenance and improvement of it. At low concentrations, Si worked on chlorophyll a fluorescence, favouring the maintenance of photosynthetic apparatus and pigments, contributing ... / Doutor
402

Promoter analysis and expression of the tomato purple acid phosphatase (TPAP1) in tobacco.

January 2004 (has links)
Suen Pui Kit. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 154-168). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract --- p.iii / List of Figures --- p.vii / List of Tables --- p.ix / List of Abbreviations --- p.x / Chapter Chapter 1: --- Introduction --- p.1 / Chapter Chapter 2: --- Literature Review --- p.3 / Chapter 2.1 --- Phosphorus and Plants --- p.3 / Chapter 2.1.1 --- Importance of phosphorus --- p.3 / Chapter 2.1.2 --- Phosphorus is a limiting nutrient --- p.3 / Chapter 2.2 --- Responses of Plants to Phosphate Deficiency --- p.4 / Chapter 2.2.1 --- Morphological changes of plants during phosphate deficiency --- p.5 / Chapter 2.2.1.1 --- Modification of the root system --- p.5 / Chapter 2.2.1.2 --- Symbiotic association of roots with mycorrhiza --- p.6 / Chapter 2.2.2 --- Maintenance of phosphate levels in plants during phosphate deficiency --- p.7 / Chapter 2.2.2.1 --- Phosphate homeostasis in plants --- p.7 / Chapter 2.2.2.2 --- "Enhancement of Pi scavenging, recycling and uptake" --- p.9 / Chapter 2.2.2.3 --- Pi-limited metabolism --- p.11 / Chapter 2.2.3 --- Hormones and phosphate starvation responses --- p.12 / Chapter 2.2.4 --- Regulation of gene expression during phosphate starvation --- p.14 / Chapter 2.2.4.1 --- The pho regulon in bacteria and yeast --- p.14 / Chapter 2.2.4.2 --- The coordination of phosphate starvation induced genes in plants --- p.19 / Chapter 2.2.4.3 --- Signaling phosphate starvation --- p.19 / Chapter 2.2.4.4 --- Phosphite and phosphate starvation --- p.21 / Chapter 2.2.4.5 --- Transcriptional regulation during phosphate starvation --- p.22 / Chapter 2.3 --- Acid Phosphatases in Higher Plants --- p.26 / Chapter 2.3.1 --- Enzymatic properties of acid phosphatases --- p.26 / Chapter 2.3.2 --- Localization and function of acid phosphatases --- p.27 / Chapter 2.3.3 --- Expression of acid phosphatases --- p.28 / Chapter 2.4 --- Purple Acid Phosphatases --- p.29 / Chapter 2.4.1 --- Properties of purple acid phosphatases --- p.29 / Chapter 2.4.2 --- Regulation and expression of plant purple acid phosphatase --- p.32 / Chapter 2.5 --- Tomato Purple Acid Phosphatases --- p.33 / Chapter 2.6 --- Promoter Analysis --- p.35 / Chapter 2.6.1 --- Structure of an eukaryotic promoter --- p.35 / Chapter 2.6.2 --- Promoter analysis by deletion mapping --- p.37 / Chapter 2.6.3 --- The computational approaches in promoter analysis --- p.38 / Chapter 2.6.4 --- Transient expression assay and transgenic expression assay --- p.39 / Chapter 2.7 --- Transcriptional Regulation of Tomato Purple Acid Phosphatase Expression --- p.40 / Chapter 2.8 --- Hypothesis --- p.41 / Chapter Chapter 3: --- Materials and Methods --- p.43 / Chapter 3.1 --- Introduction --- p.43 / Chapter 3.2 --- Materials --- p.44 / Chapter 3.2.1 --- Chemicals --- p.44 / Chapter 3.2.2 --- Plant materials --- p.44 / Chapter 3.2.3 --- Plasmid vectors and bacterial strains --- p.44 / Chapter 3.2.4 --- Primers design --- p.45 / Chapter 3.2.5 --- Confirmation of sequence fidelity --- p.46 / Chapter 3.3 --- Cloning of the TPAP1 Promoter Fragments --- p.46 / Chapter 3.3.1 --- Genomic DNA extraction --- p.46 / Chapter 3.3.1.1 --- Materials --- p.46 / Chapter 3.3.1.2 --- Procedures --- p.47 / Chapter 3.3.2 --- Cloning strategy of TPAP1 promoter --- p.47 / Chapter 3.3.3 --- TPAP1 promoter cloning --- p.48 / Chapter 3.3.3.1 --- Long-distance PCR --- p.48 / Chapter 3.3.4 --- Chimeric gene constructs --- p.48 / Chapter 3.3.4.1 --- Chimeric gene construction for particle bombardment --- p.51 / Chapter 3.3.4.2 --- Chimeric gene construction for tobacco transformation --- p.51 / Chapter 3.4 --- Transient Expression Assay of the TPAP1 Promoter Fragments --- p.54 / Chapter 3.4.1 --- TPAP1 promoter activity assay --- p.54 / Chapter 3.4.2 --- Preparation of MS culture medium --- p.54 / Chapter 3.4.3 --- Growing tomato seedlings in MS liquid medium --- p.56 / Chapter 3.4.4 --- Biolistic bombardment --- p.56 / Chapter 3.4.5 --- GUS histochemcial staining --- p.57 / Chapter 3.4.5.1 --- Materials --- p.57 / Chapter 3.4.5.2 --- Procedures --- p.57 / Chapter 3.5 --- Transgenic Assay of the TPAP1 Promoter Fragments --- p.58 / Chapter 3.5.1 --- Materials for tobacco transformation --- p.58 / Chapter 3.5.2 --- Agrobacterium tumefaciens preparation --- p.58 / Chapter 3.5.3 --- Tobacco transformation and regeneration --- p.59 / Chapter 3.5.4 --- Promoter activity analysis --- p.60 / Chapter 3.5.4.1 --- Materials --- p.60 / Chapter 3.5.4.2 --- Procedures --- p.60 / Chapter 3.5.5 --- Southern blot analysis --- p.61 / Chapter 3.5.6 --- RNA isolation --- p.61 / Chapter 3.5.6.1 --- Materials --- p.61 / Chapter 3.5.6.2 --- Procedures --- p.61 / Chapter 3.5.7 --- Northern blot analysis --- p.62 / Chapter 3.6 --- Biochemical Analysis of Acid Phosphatase Activities --- p.63 / Chapter 3.6.1 --- Excretion of acid phosphatase into the environment --- p.63 / Chapter 3.6.2 --- Growing tomato seedlings in MS medium --- p.63 / Chapter 3.6.3 --- Acid phosphatase activity assay by p-nitrophenyl phosphate --- p.64 / Chapter 3.6.4 --- Activity-gel detection --- p.65 / Chapter 3.6.4.1 --- Materials --- p.65 / Chapter 3.6.4.2 --- Procedures --- p.65 / Chapter 3.7 --- "Sequence Analysis of the TPAP1 gene, cDNA and promoter" --- p.66 / Chapter 3.7.1 --- Isolation of TPAPl cDNA --- p.66 / Chapter 3.7.1.1 --- Rapid amplification of cDNA ends (RACE) --- p.66 / Chapter 3.7.1.2 --- RT-PCR --- p.67 / Chapter 3.7.2 --- Isolation of TPAP1 gene --- p.67 / Chapter 3.7.2.1 --- PCR amplification of the TPAP1 gene --- p.67 / Chapter 3.7.2.2 --- TPAP1 gene sequence determination --- p.68 / Chapter 3.7.3 --- Sequence analysis --- p.69 / Chapter 3.8 --- Statistical analysis --- p.70 / Chapter Chapter 4: --- Results --- p.72 / Chapter 4.1 --- "Cloning of the TPAP1 Promoter Fragments, Gene and cDNA" --- p.72 / Chapter 4.1.1 --- TPAP1 promoter fragment constructs --- p.72 / Chapter 4.1.2 --- TPAP1 cDNA cloning --- p.72 / Chapter 4.1.3 --- TPAP1 gene cloning --- p.72 / Chapter 4.2 --- "Sequence analysis of the TPAP1 promoter, gene, cDNA and predicted amino acid sequence" --- p.76 / Chapter 4.2.1 --- "The DNA sequence of the TPAP1 promoter, gene and cDNA" --- p.76 / Chapter 4.2.2 --- Properties of TPAP1 cDNA and protein --- p.83 / Chapter 4.2.3 --- Identification of potential metal ligating residues on TPAP1 --- p.85 / Chapter 4.2.4 --- Phylogenetic relationship of TPAPl to other plant PAPs --- p.86 / Chapter 4.2.5 --- Sequence comparison of 5'UTR ofTPAPl and NtPAP12 --- p.89 / Chapter 4.3 --- APase Activity Assay --- p.90 / Chapter 4.3.1 --- p-NPP APase activity assay --- p.90 / Chapter 4.3.2 --- Activity-gel detection --- p.90 / Chapter 4.4 --- "Comparison of TPAP 1, IAP,SAP 1 and SAP2" --- p.96 / Chapter 4.5 --- Potential Cis-acting Regulatory Elements (CAREs) on the TPAP1 Promoter --- p.100 / Chapter 4.5.1 --- Search for potential CAREs --- p.100 / Chapter 4.5.2 --- Functions of CAREs --- p.100 / Chapter 4.6 --- Transient Expression Analysis --- p.102 / Chapter 4.6.1 --- Biolistic bombardment of TPAP1 promoter fragments into tomato roots --- p.102 / Chapter 4.7 --- Transgenic Expression Analysis --- p.104 / Chapter 4.7.1 --- Transformation of tobacco --- p.104 / Chapter 4.7.2 --- Northern and RT-PCR analysis of GUS expression --- p.110 / Chapter 4.7.3 --- GUS activity analysis --- p.114 / Chapter 4.7.4 --- Histochemical staining of GUS --- p.123 / Chapter Chapter 5: --- Discussions --- p.135 / Chapter 5.1 --- Properties ofTPAPl --- p.135 / Chapter 5.1.1 --- "Structure of the TPAP1 promoter, gene and cDNA" --- p.135 / Chapter 5.1.2 --- Potential flmction(s) ofTPAPl --- p.135 / Chapter 5.1.3 --- The potential relationship between TPAP1 and NtPAP12 --- p.137 / Chapter 5.2 --- Induction of Secretory APases during Pi Starvation --- p.137 / Chapter 5.3 --- Putative Protein Encode by theTPAP 1 cDNA --- p.138 / Chapter 5.4 --- Promoter Analysis of TPAP1 --- p.140 / Chapter 5.4.1 --- Construct preparation --- p.140 / Chapter 5.4.2 --- Potential CAREs located on the TPAP1 promoter --- p.141 / Chapter 5.4.3 --- Transient expression analysis --- p.142 / Chapter 5.4.4 --- Transgenic expression analysis --- p.143 / Chapter 5.4.4.1 --- Northern analysis and RT-PCR analysis of GUS expression --- p.143 / Chapter 5.4.4.2 --- GUS activity analysis --- p.143 / Chapter 5.4.4.3 --- Histochemical staining of GUS --- p.145 / Chapter 5.5 --- Hypothetical Model for TPAP1 Promoter Activities --- p.146 / Chapter 5.5.1 --- Model for expression level --- p.146 / Chapter 5.5.2 --- Models for spatial expressions --- p.148 / Chapter 5.6 --- Future Perspectives --- p.150 / Chapter Chapter 6: --- Conclusions --- p.152 / References --- p.154
403

Pseudomonas cichorii em tomateiro : ocorrência no Estado de São Paulo, gama de hospedeiras e reação de genótipos /

Silva Júnior, Tadeu Antônio Fernandes da, 1982- January 2007 (has links)
Resumo: Recentemente, em dois campos comerciais de tomateiro dos tipos Salada e Italiano, localizados respectivamente em Bragança Paulista e Mogi Guaçú, SP, foram observados sintomas de queima generalizada nas folhas. Em observações ao microscópio óptico de tecidos infectados foi constatada a presença de exsudação bacteriana. Isolamentos realizados em meio de cultura permitiram obter bactérias com formato bastonete, Gramnegativas, com colônias de coloração branca e produtoras de pigmento fluorescente em meio B de King. Isolados bacterianos foram submetidos a testes bioquímicos e fisiológicos, entre eles, LOPAT, sendo enquadrados no grupo III de LOPAT (- + - - +) e, portanto, identificados como sendo Pseudomonas cichorii. Esses resultados foram corroborados por testes serológicos de imunofluorescência indireta, com antissoros produzidos para isolado tipo de P. cichorii. Esta bactéria causa doença em várias culturas de importância econômica e ainda não havia sido constatada em nosso país, na cultura do tomateiro. Isolados bacterianos encontramse depositados na Coleção de Culturas de Fitobactérias do Instituto Biológico, sob os números de acesso IBSBF 2309 e IBSBF 2323. Foram desenvolvidos também estudos visando a determinação da gama de hospedeiras e a reação de 28 genótipos de tomateiro aos isolados de P. cichorii. Plantas de abobrinha, alface, beldroega, berinjela, beterraba, cenoura, couvebrócolo, datura, fumo, girassol, jiló, melão, pepino, petúnia, pimentão, rabanete, repolho, rúcula, salsa e tomateiro, no estágio de um par de folhas verdadeiras, foram inoculadas por pulverização com os isolados IBSBF 2309 e IBSBF 2323 e um isolado de P. cichorii de girassol (GIR-1). Os isolados IBSBF 2309 e IBSBF 2323 mostraram-se patogênicos à beldroega, à datura, ao girassol, ao pimentão e ao tomateiro, enquanto que o isolado de girassol foi... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Recently, generalized blight symptoms were observed in tomato leaves of the Salada and Italiano types, in two commercial fields located, respectively, in Bragança Paulista and Mogi Guaçú, SP, Brazil. The presence of bacterial exudation was verified in observations of infected tissues under the optical microscope. Rod-shaped, Gram-negative bacteria were obtained from isolations in culture medium; the colonies were white and produced fluorescent pigment in King's B medium. Bacterial isolates were submitted to biochemical and physiological tests, including LOPAT, and were classified into LOPAT group III (- + - - +); consequently, they were identified as Pseudomonas cichorii. These results were corroborated by indirect immunofluorescence tests, using antisera produced for the type isolate of P. cichorii. This bacterium causes diseases in several crops of economic importance and had not yet been observed in tomato in Brasil. Bacterial isolates were deposited in Phytobacteria Culture Collection of Instituto Biológico, under accession numbers IBSBF 2309 and IBSBF 2323. Studies were also carried out in order to determine the host range and reaction of 28 tomato genotypes to P. cichorii isolates. Caserta pumpkin, lettuce, purslane, eggplant, beet, broccoli, carrot, Jimson weed, sunflower, tobacco, scarlet eggplant, melon, cucumber, petunia, green pepper, radish, cabbage, arugula, parsley, and tomato plants, all with one pair of true leaves, were spray-inoculated with isolates IBSBF 2309 and IBSBF 2323 and one P. cichorii isolate from sunflower (GIR-1). Isolates IBSBF 2309 and IBSBF 2323 were pathogenic to purslane, Jimson weed, sunflower, green pepper, and tomatoe, while the sunflower isolate was only pathogenic to purslane, Jimson weed, and sunflower, but not to green pepper or... (Complete abstract click electronic access below) / Orientador: Antonio Carlos Maringoni / Coorientador: Luís Otávio Saggion Beriam / Banca: Margarida Fumiko Ito / Banca: Ricardo Gioria / Mestre
404

Models for estimation growth, yield and nutrients content of processing tomato /

Silva, Juliana Aparecida dos Santos da. January 2016 (has links)
Orientador: Arthur Bernardes Cecílio Filho / Coorientador: Glauco de Souza Rolim / Banca: Renato de Mello Prado / Banca: José Ricardo Mantovani / Banca: Jairo Osvaldo Cazetta / Banca: Adriano Bortolotti da Silva / Resumo: Neste trabalho foram estudados processos relacionados ao desenvolvimento e crescimento do tomate industrial. Os experimentos foram conduzidos nos anos 2013 e 2014 em três áreas diferentes da cidade de Guaíra-SP. No capítulo 1, objetivou-se calibrar e testar o modelo CROPGRO-Tomate com dados de cinco experimentos de campo com tomate industrial sob diferentes concentrações de fósforo no solo. Os tratamentos dos experimentos para calibração foram para a área 1: 0, 150, 300, 450, 600 e 750 kg ha-1 P2O5 e para as áreas dois e três: 0, 200, 400, 600, 800 e 1000 kg ha-1 P2O5, em delineamento de blocos ao acaso com quatro repetições. Nos experimentos para testar o modelo foi aplicado 450 kg ha-1 P2O5. A cada 15 dias após o transplante (DAT) plantas foram recolhidas para a medição de biomassa e área foliar. No final do ciclo de cultivo foram coletadas plantas para avaliação da produção. Todos os dados coletados foram utilizados para calibração e teste do modelo CROPGRO-Tomate. O modelo foi acurado (índice d médio = 0,91 e RRMSE médio = 0,24) para simular a resposta do tomate industrial à diferentes concentrações de P no solo. O objetivo do experimento 2 foi estimar o índice de área foliar (LAI) do tomate industrial utilizando dados obtidos por métodos destrutivos e não destrutivos, dados meteorológicos e número de folhas (NL). Os métodos de medição da área foliar foram Li-Cor (destrutivo), ImageJ e Canopeo (imagens digitais). Também para a estimativa de LAI foram utilizadas soma de grau-dias (ΣDD), radiação global (Qg) e número de folhas (NL). As fotografias foram tiradas aleatoriamente, em duas áreas diferentes a 15, 30, 45, 60, 75, 90, 105 e120 DAT utilizando um quadro vazado de 1 m2 de área colocado sobre as plantas. As fotografias foram tiradas em 24 pontos diferentes, em cada ponto foi coletada uma planta para ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In this work were discussed processes related to development and growth of processing tomato. The experiments were conducted in the years 2013 and 2014 in three different areas in the city of Guaíra-SP. In chapter 1 the objective was to calibrate and test the CROPGRO-Tomato model with data of five field experiments with processing tomato under different phosphorus concentrations in the soil. The treatments of experiments for calibration were for the area 1: 0, 150, 300, 450, 600 and 750 kg ha-1 P2O5 and for the areas two and three: 0, 200, 400, 600, 800 and 1000 kg ha-1 P2O5, in randomized block design with four replications. The experiments for testing the model 450 kg ha-1 P2O5 was applied. In each 15 days after transplanting (DAT) plants were collected for measuring biomass and leaf area. At the end of crop cycle plants were collected for evaluation of production. All data collected were used for calibration and testing of CROPGRO-Tomato model. The model was accurate (average d index = 0.91, average RRMSE = 0.24) to simulate response of processing tomato to different soil P concentrations. The objective of Experiment 2 was to estimate the leaf area index (LAI) of processing tomato using data obtained by destructive and non-destructive methods, meteorological data and number of leaves (NL). For Experiment 2 the methods of measuring leaf area were Li-Cor (destructive), ImageJ and Canopeo (digital images). Also for estimation of LAI it were used sum of degree-days (ΣDD), global radiation (Qg) and number of leaves (NL). Photographs were taken at random, in two different areas at 15, 30, 45, 60, 75, 90, 105, DAT 120 using a 1m2 square frame placed over the plants. Photographs were taken in 24 different points, in each point it was collected one plant for leaf area measurement using Li-Cor and leaves counting. LAI ... (Complete abstract click electronic access below) / Doutor
405

Caracterização química de tomates (Lycopersicon esculentum Mill.) empregando análise por ativação neutrônica instrumental / Chemical characterization of tomatoes (Lycopersicon esculentum Mill.) by using instrumental neutron activation analysis

Ferrari, Angela Aparecida 30 September 2008 (has links)
O tomate é a segunda hortaliça mais produzida no mundo, superada apenas pela batata, com participação efetiva na dieta humana. O seu valor como alimento traz um paradoxo. Ao mesmo tempo em que é elogiado por ser considerado um alimento funcional, com propriedades nutracêuticas, sofre críticas pela forma como é normalmente produzido, sob pesadas quantidades de fertilizantes sintéticos e pesticidas. Há muitas causas de variação que podem alterar a composição dos frutos. Neste sentido, o presente trabalho procurou coletar amostras em um universo que engloba diferentes fatores, incluindo cultivares para o consumo in natura e para o processamento industrial, sistemas de cultivo convencional e orgânico, regiões geográficas e tipos de solo. O objetivo geral foi caracterizar o tomate quanto aos elementos químicos visando a identificação daqueles de interesse agronômico ou nutricional e o estabelecimento das faixas de concentrações para frutos produzidos sob as fontes diversas de variação. Objetivos específicos envolveram estudos de representatividade amostral e de influência dos estádios de maturação e do solo na composição química dos frutos. Os tomates das cultivares AP 533, Colibri e T-92 foram coletados em propriedades localizadas em municípios do estado de São Paulo. A determinação dos elementos químicos foi feita pelo método primário de análise por ativação neutrônica instrumental (INAA). A qualidade do procedimento analítico foi verificada por meio da exatidão e da reprodutibilidade dos resultados com o emprego de materiais de referência. O estudo de representatividade amostral revelou que o número necessário de amostras para representar o tomate no campo foi inferior a 12, considerando um erro máximo admitido pelo analista de 15%. A variabilidade intra-amostral foi avaliada por meio de 12 repetições analíticas de uma mesma amostra e os resultados indicaram a homogeneidade do material. Os elementos químicos Br, Ca, Co, Cs, Fe, K, La, Na, Rb, Sr e Zn foram determinados nas amostras de polpas, sementes e solos. A análise de frutos nos estádios de maturação verde maduro e rosado indicou maiores concentrações de Ca, Fe, K, Na, Rb e Sr nos tomates rosados, enquanto Br, Co, Cs e Zn não apresentaram diferenças significativas (p < 0,05). Os solos das seis propriedades estudadas apresentaram composição química bastante diferenciada. Contudo, não foram observadas correlações das concentrações de elementos químicos encontradas nas amostras de polpa e de solo. Os resultados da caracterização química dos tomates permitiram realizar importantes inferências com relação ao comportamento dos elementos químicos. K e Ca foram os nutrientes mais abundantes na polpa e na semente. As concentrações de Br, Co, Cs, Rb e Sr na polpa diferiram significativamente (p < 0,05) tanto entre sistemas de cultivo como entre cultivares. Fe, K, Na e Zn na polpa não foram afetados pelos sistemas de cultivo, sendo as diferenças encontradas intrínsecas para cada cultivar. As polpas e as sementes dos tomates das três cultivares não apresentaram diferenças para Ca. Br permitiu a separação entre tomates orgânicos e convencionais, com concentrações maiores em tomates convencionais. Análises multivariadas revelaram que as amostras de polpa possuem uma tendência de agrupamento por categorias, tanto em termos de cultivar como de sistema de cultivo, embora esse último fator tenha apresentado resultados menos evidentes. Por outro lado, as sementes apresentaram maior tendência de agrupamento pelo fator cultivar / The tomato is the second most cultivated vegetable after the potato, having an effective participation in the human diet. Its food value remains paradoxical. At same time it is recognized as a functional food with nutraceutical properties, the tomato receives criticism due to the way it is usually cultivated, i.e. under heavy amounts of synthetic fertilizers and pesticides. There are many causes of variation that may change the fruit composition. In this aspect, the current work aimed at collecting samples in a universe that comprises different factors, including cultivars for fresh market and for processing, conventional and organic cultivation systems, geographical regions and soil types. The main objective of this work was the chemical element characterization of tomato in view of the identification of elements of agronomical and nutritional interest and establishing concentration ranges for the fruits produced under different sources of variation. The specific objectives comprehended studies of sample representativeness and studies of the influence of ripening stages and soil on the chemical composition of tomato fruits. Tomatoes from the cultivars AP 533, Colibri and T-92 were sampled in farms located in cities of São Paulo State. The determination of the chemical elements was carried out by using the primary method of measurement instrumental neutron activation analysis (INAA). The quality of the analytical procedure was evaluated by means of accuracy and reproducibility of reference materials results. The study of sample representativeness showed that the required number of 12 samples to represent the tomato in the field, considering 15% as the maximum deviation allowed by the analyst. The within-sample variability was evaluated by means of 12 analytical portions taken from one sample. The results demonstrated the homogeneity of the material. The chemical elements Br, Ca, Co, Cs, Fe, K, La, Na, Rb, Sr and Zn were determined in the samples of pulp, seeds and soils. The analysis of fruits at mature green and pink stage indicated higher concentrations of Ca, Fe, K, Na, Rb and Sr in the tomatoes at pink stage, while Br, Co, Cs and Zn did not show any significant difference (p < 0.05). The soils from the six studied farms presented different chemical compositions. However, no correlations were observed between the chemical element concentrations found in the samples of pulp and soil. The results of chemical characterization of tomatoes allowed making important inferences with relation to the chemical elements behavior. K and Ca were the most abundant nutrients in the pulp and seeds. Br, Co, Cs, Rb and Sr concentrations in the pulp showed significant differences (p < 0.05) for both cultivation systems and cultivars. Fe, K, Na and Zn concentrations in the pulp were not affected by the cultivation systems, being the differences found intrinsic to each cultivar. The pulp and seeds from the tomatoes of the three cultivars did not present any significant difference for Ca. Br allowed the discrimination of organic and conventional tomatoes, the later showing the higher concentrations. Multivariate analysis of the pulp results revealed a trend in clustering by categories, both in terms of cultivars and cultivation system, although the later showed less clear results. On the other hand, the seeds presented higher trend in clustering by the cultivar factor
406

Interactive effects of nemarioc-al and nemafric-bl phytonematicides on growth and foliar nutrient elements of tomato cultivar 'HTX 14' plants

Maake, Mafutha Violet January 2018 (has links)
Thesis (MSc. Agriculture (Horticulture)) -- University of Limpopo, 2018 / The production of tomato (Solanum lycopersicum L.) plants had been crucial in various parts of the world since tomato fruit contribute widely to human health. However, most tomato cultivars had been shown to be highly susceptible to plant-parasitic nematodes, especially the root-knot (Meloidogyne species) nematodes. Two cucurbitacin-containing phytonematicides, namely, Nemarioc-AL and Nemafric-BL phytonematicides, manufactured from fruits of Cucumis species, are being researched and developed in South Africa as an alternative for management of Meloidogyne species. Most trials on tomato plants and cucurbitacin-containing phytonematicides had been under greenhouse conditions, with limited information on their interactive effects under microplot and field conditions. The objectives of this study were: (1) to determine the interactive effects of Nemarioc-AL and Nemafric-BL phytonematicides on growth and accumulation of nutrient elements in leaf tissues of tomato plants under microplot conditions and (2) to investigate the interactive effects of Nemarioc-AL and Nemafric-BL phytonematicides on growth and accumulation of nutrient elements in leaf tissues of tomato plants under field conditions. In the microplot study, uniform four-week-old tomato cv. 'HTX 14' seedlings were transplanted in 4 L plastic bags containing loam soil and Hygromix-T at the 3:1 ratio (v/v). Plastic bags were inserted into holes at 0.50 m inter-row spacing and 0.60 m intra-row spacing. The 2 x 2 factorial trial, with the first and second factors being Nemarioc-AL and Nemafric-BL phytonematicides, respectively, each at two levels. The four treatments, namely, AL0BL0, AL0AL1, BL0BL1 and AL1BL1, were arranged in a randomised complete block design. Treatments were xxiv applied seven days after transplanting and repeated weekly until harvest. Under field conditions, uniform four-week-old tomato cv. 'HTX 14' seedlings were transplanted into the field at 0.50 m inter-row spacing and 0.60 m intra-row spacing. Treatments, experimental designs and application interval were as those under microplot conditions. At 60 days after the treatments, seedlings AL × BL interaction was not significant on all plant variables in Experiment 1 under microplot conditions, whereas in Experiment 2 the interaction was highly significant (P ≤ 0.01) on dry shoot mass, contributing 72% in total treatment variation (TTV) of the variable. Relative to untreated control, the two-way matrix showed that the interaction reduced dry shoot mass by 8%. Nemarioc-AL phytonematicide had a significant (P ≤ 0.05) effect on stem diameter in Experiment 1 under field conditions, whereas Nemafric-BL phytonematicide had significant effects on plant height in Experiment 2, contributing 39 and 56% in TTV of the respective variables. Relative to untreated control, Nemarioc-AL phytonematicide increased stem diameter by 4%, whereas Nemafric-BL phytonematicide increased plant height by 2%. The interaction was also significant (P ≤ 0.05) on Na and S and highly significant (P ≤ 0.01) on Zn, contributing 76, 26 and 6%, respectively, in TTV of the respective variables in Experiment 1 under field conditions. Using a two-way matrix, the interaction increased Na and S by 12 and 41%, respectively, but reduced Zn by 52%. In Experiment 2, the interaction was highly significant (P ≤ 0.01) on P alone, contributing 16% in TTV of the variable, with the interaction reducing P by 76%. Nemarioc-AL phytonematicide had significant effects (P ≤ 0.05) on Ca and highly significant effects (P ≤ 0.01) on S, contributing 31 and 58% in TTV of the respective variables in Experiment 1. Relative to untreated control, Nemarioc-AL phytonematicide increased P by 39%. In xxv Experiment 2, Nemarioc-AL phytonematicide had significant effects on Ca and highly significant effects (P ≤ 0.01) on S, contributing 66 and 49% in TTV of the respective variables. Relative to untreated control, Nemarioc-AL phytonematicide reduced Ca by 19% and S by 36%, respectively. Nemafric-BL phytonematicide had a significant effect (P ≤ 0.05) on P, contributing 33% in TTV of the variable in Experiment 1. Relative to untreated control, Nemafric-BL phytonematicide increased P by 41%. In Experiment 2, Nemafric-BL phytonematicide had significant effects (P ≤ 0.05) on S, contributing 40% in TTV of the variable. Relative to untreated control, Nemafric-BL phytonematicide reduced S by 33%. At 74 days after initiating the treatments under field conditions, the interaction of Nemarioc-AL and Nemafric-BL phytonematicides were not significant for plant height, stem diameter, fresh fruit and dry shoot mass in both experiments. Nemarioc-AL phytonematicide was also not significant in all plant variables in both experiments. Effects of Nemafric-BL phytonematicide were highly significant on dry shoot mass in Experiment 1 and stem diameter in Experiment 2, contributing 60 and 67% in TTV of the respective variables. Relative to untreated control, Nemafric-BL phytonematicide reduced dry shoot mass by 28% and increased stem diameter by 11% in Experiment 1 and Experiment 2, respectively. The AL × BL interaction had significant effects (P ≤ 0.05) on P, contributing 57% in TTV of the variable in Experiment 1. Relative to untreated control, the interaction increased P by 12%. In Experiment 2, the interaction had significant effects (P ≤ 0.05) on K, Mg, S and Mn, contributing 78, 65, 74 and 68% in TTV of the respective variables. Using a two-way matrix, relative to untreated control, the interaction increased K by 8%, but reduced Mg, Mn and S by 14, 82 and 1%, respectively. Nemarioc-AL phytonematicide was not significant in both the xxvi experiments, whereas Nemafric-BL phytonematicide had significant effects on Mg in Experiment 1, contributing 68% in TTV of the variable. Relative to untreated control, Nemafric-BL phytonematicide increased Mg by 15%. In conclusion, the interaction of Nemarioc-AL and Nemafric-BL phytonematicides were not compatible with each other as they had undesirable effects on growth of tomato plants and accumulation of most essential nutrient elements in leaf tissues of this plant. / National Research Foundation (NRF)
407

Microflora in the root environment of hydroponically grown tomato : methods for assessment and effects of introduced bacteria and Pythium ultimum /

Khalil, Sammar. January 2001 (has links)
Thesis (doctoral)--Swedish University of Agricultural Sciences, 2001. / Includes bibliographical references.
408

Organik domates yetiştiriciliğinde çiftlik gübresi,mikrobiyal gübre ve bitki aktivatörü kullanımının verim, kalite ve bitki besin maddeleri alımına etkileri /

Ünlü, Hüsnü. Padem, Hüseyin. January 2008 (has links) (PDF)
Tez (Doktora) - Süleyman Demirel Üniversitesi, Fen Bilimleri Enstitüsü, Bahçe Bitkileri Anabilim Dalı, 2008. / Kaynakça var.
409

EFFECT OF CYTOKININS AND GIBBERELLINS ON FLOWERING AND FRUIT SET OF TOMATO (LYCOPERSICON ESCULENTUM MILL.) UNDER HIGH TEMPERATURE

Satti, Satti Mohamed Elzein January 1981 (has links)
Tomato plants (Lycopersicon esculentum Mill.) were grown in the greenhouse and in the field during 1979 and 1980. The inflorescences were treated with gibberellin (GA4/7) and/or benzyladenine (BA). Root exudate was collected at various stages of growth and development for the estimation of the levels of cytokinins in the plant. Soluble sugars and starch were determined in inflorescences at different stages of development. Partitioning of dry matter between the different plant portions was studied to evaluate growth of tomato plants in two different conditions. The application of GA4/7 and BA to tomato inflorescences promoted the development and increased the number of flowers. These growth regulators substantially increased fruit set and yield of tomatoes in both greehouse and field experiments. Determinations of carbohydrates in inflorescences treated with growth regulators showed higher amounts of soluble sugars and starch over a considerable period of development. The level of cytokinins in root exudate was higher during early phase of vegetative growth. At the time of bud formation and anthesis, the level of cytokinins declined. The quantity of translocated cytokinins in the greenhouse was 4 to 5 times higher than under high temperatures in the field. The low levels of cytokinins were associated with poor flower development. Field grown tomato plants produced more vegetative growth and fewer inflorescences than plants in the greenhouse. Allocation of assimilates to newly developed leaves and low level of growth regulators in buds and inflorescences might contribute towards more vegetative growth but poor flowering under high temperatures.
410

PLANT GROWTH REGULATOR IN MUNICIPAL WASTEWATER

Wilson, John R. (John Robert), 1936- January 1982 (has links)
No description available.

Page generated in 0.0336 seconds