This thesis explores debates around seed governance in the context of Tanzania’s recent changes to its seed policies and laws, in order to critically examine the framings and discourses employed. Three narratives emerge, Seed Capitalism, Seed Pluralism, and Seed Sovereignty. Consistent with Westengen (2017), Seed Capitalism and Seed Sovereignty rely on, and are entrenched in, binary opposition, despite the complexity of the problems involved, and put forward singular solutions that risk harming smallholder resilience. Seed Capitalism portrays scientist-bred certified seed as superior to farmer varieties, and as optimal for smallholders, despite evidence to the contrary. Seed Sovereignty constructs rigid distinctions between peasant seeds and industrial seeds, failing to engage with the phenomenon of creolized seed, the intermixing of farmer varieties with scientist-bred varieties. Creolized seed presents a narrative threat to Seed Sovereignty’s rejection of industrial seed. Both Seed Capitalism and Seed Sovereignty narratives obscure evidence relating to seed quality and yield that is in tension with their underlying agendas. A third discourse, Seed Pluralism, not previously identified as such by the literature, resists binary framings and recommends a multiplicity of approaches informed by the nuance of relevant facts. Tanzania’s seed governance framework predominantly reflects the Seed Capitalism discourse. While Seed Pluralism has a small foothold in Tanzania’s seed governance, through the Quality Declared Seed (QDS) system, overall Tanzania’s seed laws are threatening smallholder resilience. Positive reform under Tanzania’s current political settlement is unlikely. Pro-poor donors should withdraw support for governance frameworks rooted in Seed Capitalism, and instead promote seed governance reforms grounded in Seed Pluralism, including eliminating restrictions on smallholder seed exchange in low income countries.

Submitted by JULIANA JOICE PEREIRA LIMA null (julianajoicelima@yahoo.com.br) on 2016-06-28T20:01:19Z No. of bitstreams: 1 Final_version_UNESP com ficha.pdf: 2890371 bytes, checksum: 99c3a37a64a79be1ed5e60fb7720deb9 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-06-29T18:48:22Z (GMT) No. of bitstreams: 1 lima_jjp_dr_bot_par.pdf: 731237 bytes, checksum: 6b7a35a2397a27e5b7522bcee2cf6435 (MD5) / Made available in DSpace on 2016-06-29T18:48:22Z (GMT). No. of bitstreams: 1 lima_jjp_dr_bot_par.pdf: 731237 bytes, checksum: 6b7a35a2397a27e5b7522bcee2cf6435 (MD5) Previous issue date: 2016-04-29 / Item withdrawn by Maria Lucia Martins Frederico null (mlucia@fca.unesp.br) on 2018-10-09T12:55:09Z Item was in collections: Teses - Agronomia (Agricultura) - FCA (ID: 320) No. of bitstreams: 3 lima_jjp_dr_bot_par.pdf.jpg: 3708 bytes, checksum: f4776b7545f49e0381732de6fe127643 (MD5) lima_jjp_dr_bot_par.pdf.txt: 70796 bytes, checksum: a8b790348c0cd59ac464aff1569d634a (MD5) lima_jjp_dr_botfca.pdf: 2807174 bytes, checksum: 00e8dea3c713cb320435c39d6d97bae6 (MD5) / Item reinstated by Vivian Rosa Storti null (vstorti@reitoria.unesp.br) on 2018-10-10T14:33:51Z Item was in collections: Teses - Agronomia (Agricultura) - FCA (ID: 320) No. of bitstreams: 3 lima_jjp_dr_bot_par.pdf.jpg: 3708 bytes, checksum: f4776b7545f49e0381732de6fe127643 (MD5) lima_jjp_dr_bot_par.pdf.txt: 70796 bytes, checksum: a8b790348c0cd59ac464aff1569d634a (MD5) lima_jjp_dr_botfca.pdf: 2807174 bytes, checksum: 00e8dea3c713cb320435c39d6d97bae6 (MD5) / Item reinstated by Vítor Silvério Rodrigues (vitor.s.rodrigues@unesp.br) on 2018-11-06T19:07:52Z Item was in collections: Teses - Agronomia (Agricultura) - FCA (ID: 320) No. of bitstreams: 5 lima_jjp_dr_bot_par.pdf.jpg: 3708 bytes, checksum: f4776b7545f49e0381732de6fe127643 (MD5) lima_jjp_dr_botfca.pdf.jpg: 4544 bytes, checksum: af481a0bb7992130d84da3a17c3b7c0d (MD5) lima_jjp_dr_bot_par.pdf.txt: 70796 bytes, checksum: a8b790348c0cd59ac464aff1569d634a (MD5) lima_jjp_dr_botfca.pdf.txt: 211012 bytes, checksum: 72d4f897af91998bbeca736aa4fc7e7f (MD5) lima_jjp_dr_botfca.pdf: 2807174 bytes, checksum: 00e8dea3c713cb320435c39d6d97bae6 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Le soja est l'une des plus importantes espèces de cultures d'huile utilisée aussi bien en nourriture que dans diverses gammes d'applications industrielles. C'est pourquoi produire des graines vigoureuses est un levier essentiel pour augmenter efficacement de la production de la récolte. La qualité de graine physiologiquement faible, qui est plus à même de se produire sous un environnement tropical, mène à un pauvre établissement des plantes ainsi qu'à une diminution du rendement. La longévité d'une graine est la capacité de celle-ci à survivre à la sécheresse durant de longues périodes et représente une caractéristique importante sur la qualité d'une graine. Ici, l'objectif était d'obtenir une idée sur les mécanismes en régulant l'acquisition progressive de la longévité. En utilisant le séquençage à haut-débit, ARN a été séquencé en sept différentes étapes durant l'acquisition de longévité, générant entre 14 et 38 millions de reads. Ces reads ont été alignés sur les modeles de gene de Glycine max Wm82.a2.v1. Les transcripts différentiellement exprimés (DET) sont corrélée avec l'augmentation de la longévité de la graine. L’analise d’enrichissement via GO de ces DET ont révélé une importante surreprésentation des termes associés à la réponse au stress et traitement et modification de l'ARN. Le processu biologique Photosynthèse était liée à une faible longévité des semences. HSF (heat shock factor) et plusieurs facteurs de transcription associés à la défense biotique (WRKY 3 et NLFX1) sont des gènes candidats dont putative rôle dans la longévité des graines et méritent une caractérisation plus poussée. Nous avons également effectué la détermination de la teneur en sucres solubles non réducteurs, et nous avons observé que l'accumulation de sucres solubles non réducteurs sont liés à l'acquisition de la longévité, mais seulement l’accumulation d’eux ne suffit pas à expliquer la croissance de la longevité. / Soja é uma das mais culturas oleaginosas usadas para alimentação animal e humana bem como para uma larga aplicação industrial. Dada a sua capacidade de fixar nitrogênio atmsférico, é fundamental para o desenvolvimento de uma agricultura sustentável. Produzir sementes altamente vigorosas é a chave para aumentar a eficiência da produção da cultura. Longevidade de semente é a capacidade de sobreviver no estado seco por períodos prolongados e representa uma importante característica de qualidade da semente. Nesta pesquisa o objetivo foi obter insights sobre processos moleculares que regulam a aquisição de longevidade em sementes de soja. Com o sequenciamento de nova geração da Illumina, o RNA foi sequenciado a partir de sete estágios diferentes durante a aquisição de longevidade, gerando entre 14 e 38 milhões de reads. Estes reads foram alinhados com os modelos de genes de Glycine max Wm82.a2.v1 preditos no genoma de soja. Transcritos diferencialmente expressos (DET) foram correlacionados com o aumento da longevidade. Análise de enriquecimento da ontologia do gene daqueles DET revelaram uma siginificante sobre representação de termos associados com resposta a estresse e processamento e modificação de RNA. Processo biológico fotossíntese foi relacionado à baixa longevidade. Heat Shock Factors (HSF) e vários fatores de transcrição associados com resposta a estresse biótico (WRKY e NFXL1) são genes candidatos com possíveis papéis na longevidade de semente e merecem uma caracterização. Também foi determinado o conteúdo de açúcares solúveis não redutores. Foi observado que o acúmulo desses açúcares estão relacionados à aquisição da longevidade, porém somente eles não são suficientes para explicar o ganho da longevidade. / Soybean is one of the most important oil crop species used for food and feed as well as a range of industrial applications. However, producing highly vigorous seeds is a key lever to increase crop production efficiency. Low physiological seed quality, which is more prone to occur under tropical environment, leads to poor stand establishment and decreased in yields. Seed longevity is the ability to survive the dry state for prolonged periods of time and represents an important trait for seed quality. Here, the objective was to obtain insights into the mechanisms regulating the progressive acquisition of longevity. Using Illumina high-throughput sequencing, RNA was sequenced from seven different stages during the acquisition of longevity, generating between 14 and 38 million of reads. These reads were aligned to the Glycine max Wm82.a2.v1 gene model. Differentially expressed transcripts (DET) were correlated with the increase in seed longevity. Transcriptome and GO enrichment analyses of these DET revealed a significant over-representation of terms associated with response to stress and RNA processing and modification. Photosynthesis biological process was related to low seed longevity. HSF and several TF associated with biotic defense (WRKY3 and NLFX1) are candidate genes whose putative role in seed longevity deserve further characterization. We also performed the determination of the content of non-reducing soluble sugars, and we observed that the accumulation of non-reducing soluble sugars are related to acquisition of longevity but only the accumulation of them is not enough to explain the increase in longevity.

Seed production is an important sector in crop production with high added value. Quality seed enables to exhibit the characteristics of the grown variety and to utilize its revenue potential. The diploma thesis features an analysis of the current market situation with organic certified seed in the Czech Republic in terms of the structure of seed multiplication areas, the quantity of recognized certified seed and permitted conventional untreated seed. Further assessment deals with the need for organic certified seed compared to current production in organic farming, evaluation of the structure of currently used seed in organic farming and possible causes of the lack of organic seed are also determined, including the proposed action. The literature review focuses on environmental seed production legislation, propagation, quality and seed control. The results of this thesis suggest that organic seed is propagated in the CR in an insufficient extent, for example, in comparison with neighbouring Austria. The quantity of organic certified seed in the CR is currently insufficient and does not cover the organic farming needs for growing major crops. Farm saved seed and permitted conventional untreated seed are predominantly used to establish vegetation. Organic seed was used in the minimum quantities.

Thesis aims to evaluate the performance of certified and farming potato seed cultivars of Red Anna and Monika. Following aspects were evaluated: number of full-grown, tuber yield, the average number of tubers in a bunch, the average weight of tubers in a bunch, the average weight of one tuber and starch content. The experiment started in 2013 on the farm of Ing. Tomáš Dušička in Plasy. In the experiment there were used cultivars of Red Anna and Monika because of good reputation. Certified seed was used in reproduction level C2, farmer seed was gained in the same location. Tubers were planted on the 5th May 2013, using two row seed planter (row spacing 75cm and tuber distance 25cm). Tubers were planted in the height of 16cm. In the planted rows of field experiment there was marked area of 10m2 per repetition, which requires 45 full-grown bunches in the plot. Harvest of experimental plots was carried out manually since 15th to 17th September 2013. Each bunch was dug, then the total number of tubers in a bunch was counted. Finally, the whole bunch was weighted. Tubers were sorted into two categories by size using sieve (mesh size 40mm). Both categories were weighted. Study results reveal that in the first year of planting of own farm seed may not significantly affect the yield and starch content. In case of farm seed of Monika cultivar there was 12% increase in revenue and slightly higher yield of tubers for consumption.

Made available in DSpace on 2014-06-11T19:28:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-05-29Bitstream added on 2014-06-13T19:57:56Z : No. of bitstreams: 1 galindo_cam_me_jabo.pdf: 862767 bytes, checksum: af26a620af6aa1461436f3ff8272fde7 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Com o objetivo de estudar a dormência tegumentar e caracterizar possíveis relações entre tamanho e qualidade fisiológica e permeabilidade dos tegumentos, qualidade fisiológica e permeabilidade dos tegumentos, teor de água inicial e qualidade fisiológica de sementes de mucuna preta, foram conduzidos os seguintes experimentos: determinação do teor inicial de água dos lotes (RAS); DIC, 4 repetições de 25 sementes cada; peso de 100 sementes, 4x100, DIC; teste de %G e IVG 4x25 cada, DIC; 12 tratamentos para superação de dormência; classificação dos lotes em três classes de tamanho; teor inicial de água das sementes de diferentes tamanhos (RAS), DBC, repetições 4x25, fatorial 6 lotes x 3 tamanhos; curvas de embebição com dados em dispersão e uso de função polinomial de quarto grau, dados obtidos pela razão peso final(PF)/peso inicial(PI); teste de CE com repetições 4x25, DIC, fatorial 6 lotes x 3 tamanhos, substrato solo/areis. Os lotes apresentaram relação positiva inversa para teor de água inicial em relação à germinação; resultados dos tratamentos para superação de dormência com interações para lotes e para tamanhos dentro dos lotes; os testes demonstraram haver maior interação entre lotes, ocorrendo o contrário para a variável tamanho de sementes. Concluiu-se que: sementes pequenas são mais permeáveis em lotes não dormentes; entre lotes de germinações semelhantes o de menor teor de água inicial é o de maior vigor; sementes grandes produzem mais fitomassa e o tratamento mais eficiente para quebra de dormência foi escarificação com ácido sulfúrico concentrado (98%) por 7 minutos. / Aiming to study damage and characterize possible relationships between size and physiological quality; size and coat permeability; physiological quality and tegument permeability; initial content of water and physiological quality of mucuna preta sedes (Stizolobium aterrimum Pierce & Tracy) the following experiments were conducted: análisis of water content of seed lots by oven meted at 105°C during 24 hours using with four replications of 100 seeds each; germination test (%G) and speed of germination index (SGI) with four replications of 25 seeds in complete randomized design; twelve treatments to break dormancy The seed lots presented inverse positive relationship for water content related to germination; treatment to break dormancy with interaction between lotsand seed sizes within lots; the tests demonstrated higher interaction between lots, occuring the inverse for the variable seed size; the imbibition curve proved to be na important tool in studies related with tegument permeabillity and levels of vigor among lots. The following conclusion can be withdrawn form data: small sedes are more permeable in nondormant lots; seed lots with similar germination or with lower water content, higher is the vigor; large sedes produce higher amount of phytomass. The best treatment to break seed dormancy of mucuna preta seed was acid escarification during seven minutes.

Un nombre croissant d’applications Laser nécessite l’utilisation de sources impulsionnelles présentant une grande modularité en termes de durée, de puissance et de fréquence des impulsions Laser générées. Ces sources s’appuient sur une architecture bien connue, basée sur un amplificateur de puissance à oscillateur maître (MOPA) et intégrée dans un grand nombre de systèmes d’amplification optique. Généralement, elle se compose d’une diode « seed » jouant le rôle d’un oscillateur « source » et pilotée en régime impulsionnel fournissant des impulsions optiques à un étage d’amplification (solide ou fibré), dopé avec des éléments terres rares (ex. Ytterbium). Néanmoins, la puissance crête émise par ce type de diodes dépasse rarement quelques centaines de mW. Afin d’obtenir, en sortie du « MOPA », des impulsions d’une puissance de plusieurs dizaines de kW, il est donc nécessaire de concevoir une chaîne d’amplification optique possédant un gain élevé mais en contrepartie susceptible de générer des phénomènes optiques non-linéaires néfastes à l’application. L’utilisation de diodes Laser monomode commercialisées, à très haute fiabilité, dans des régimes de polarisation en courant crête très élevé mais sous des durées d’impulsion très courtes (très inférieures à 1μs), apparaît comme une solution alternative mais impose d’être validée tant sur le plan de la caractérisation électro-optique de ces diodes que sur la robustesse de leurs performances dans ces régimes critiques de fonctionnement. / A growing number of Laser applications requires the use of pulsed sources with a large versatility in terms of duration, power and frequency of the generated Laser pulses. Such sources are based on the well-established “Master Optical Power Amplifier” architecture, and integrated into a large variety of optical amplification systems. Generally, it is composed of a “seed” diode, acting as a “source” oscillator, operated in pulse regime in order to produce optical pulses forwarded to an amplification stage (solid or fibered), doped with rare earth elements (ex. Ytterbium). However, the maximum output power delivered by such diodes barely reaches a few hundred mW. In order for the “MOPA” to produce output pulses with a peak power reaching a few tens of kW, it is necessary to design an amplification chain with a high optical gain but on the other hand susceptible to generate non-linear phenomena detrimental to the application. The use of commercialized and ultra-reliable single mode Laser diodes, operating in large overcurrent but under short pulse conditions (under 1μs), appears as an alternative solution, which, however, requires to be validated in terms of electro-optical characterizations as well as in terms of performances robustness under these critical conditions.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-03-29T12:49:53Z No. of bitstreams: 1 Amanda de Araujo Lima.pdf: 855538 bytes, checksum: 59a4fcb96a7f2232a19479da3c2f4cd6 (MD5) / Made available in DSpace on 2017-03-29T12:49:53Z (GMT). No. of bitstreams: 1 Amanda de Araujo Lima.pdf: 855538 bytes, checksum: 59a4fcb96a7f2232a19479da3c2f4cd6 (MD5) Previous issue date: 2014-09-30 / The experiments were carried out at the Laboratory of Seed Analysis - (LSA) of the Universidade Federal Rural de Pernambuco/Unidade Acadêmica de Garanhuns UFRPE/UAG in Garanhuns-Pernambuco. The fruits and the stakes of Pachira aquatica Aubl. were collected from five mother trees located on the campus of UFRPE/UAG, aiming to evaluate the physiological quality of seeds of P. aquatica subjected to drying, and salt stress, and the influence of plant extracts the rooting of P. aquatica to contribute to scientific and technical knowledge to deploy this new oilseed areas in the state of Pernambuco. The first experiment was conducted with seed drying at temperature of 35 ºC, the following exposure periods of 0 (without drying), 24, 48, 72 and 96 hours; and evaluated the water content, germination, first count and rate of germination rate, length and dry weight of roots and shoots of seedlings. Data were subjected to analysis of variance and regression. The second experiment simulation of salt stress was performed using as solute sodium chloride (NaCl) at concentrations of 0,0 (control); 3,0; 6,0; 9,0; 12,0 and 15,0 dS.m-1 diluted in distilled and deionized water, then the seeds were germinated at temperatures of 25 ºC and 30 ºC. The experimental design was completely randomized, and evaluated the germination percentage, speed of germination, seedling length (root and shoot) and dry mass of shoots. In the third experiment the rooting of P. aquatica immersed in water, immersion in commercial fertilizer Forth®, immersion extract of Salix babylonica (10, 25, 50 and 100%) and immersion in extract of Cyperus rotundus was performed (10, 25, 50 and 100%). Treatments were arranged in completely randomized design, and 60 days after planting the cuttings were conducted evaluations of rooting percentage, number of roots/cuttings, number of shoots, number of leaves, number of cuttings with shoots and dry weight leaves. The seeds of Pachira aquatica species are scattered with very high water content (55%), and a small reduction in value commits physiological quality, allowing the characterization of the seeds of this species as recalcitrant. Increasing the salt concentration in the substrate reduces the germination and seed vigor P. aquatica, especially when the seeds are subjected to a temperature of 25 ºC. P. aquatica seeds are tolerant to salinity, temperature under 30 ºC, with a reduction in seed germination at concentrations above the concentration of 6.0 dS.m-1. The P. aquatica is an easy to root species, the use of commercial fertilizer and phytohormone Forth® not necessary. The application of leaf extracts of Cyperus rotundus and Salix babylonica not a viable alternative in the production of seedlings of P. aquatica. / Os experimentos foram realizados no Laboratório de Análise de Sementes - (LAS) da Universidade Federal Rural de Pernambuco/Unidade Acadêmica de Garanhuns UFRPE/UAG, em Garanhuns-PE. Os frutos e as estacas de Pachira aquatica Aubl. foram coletados de cinco árvores matrizes localizadas na UFRPE/UAG, com o objetivo de avaliar a qualidade fisiológica das sementes de P. aquatica submetidas à secagem, ao estresse salino, e a influência de extratos vegetais no enraizamento das estacas. No primeiro experimento foi realizado à secagem das sementes sob temperatura de 35 ºC, pelos seguintes períodos de exposição: 0 (sem secagem), 24, 48, 72 e 96 horas; e avaliados o teor de água, germinação, primeira contagem e índice de velocidade de germinação (IVG), comprimento e massa seca da raiz e parte aérea das plântulas. No segundo experimento foi realizada a simulação do estresse salino utilizando-se como soluto o cloreto de sódio (NaCl), nas concentrações de 0,0 (controle); 3,0; 6,0; 9,0; 12,0 e 15,0 dS.m-1 diluídas em água destilada e deionizada, posteriormente as sementes foram postas para germinar nas temperaturas de 25 ºC e 30 ºC. O delineamento experimental utilizado foi o inteiramente ao acaso, e foram avaliadas a porcentagem de germinação, IVG, comprimento de plântulas (raiz e parte aérea) e massa seca da parte aérea. O terceiro experimento foi realizado o enraizamento de estacas de P. aquatica imersas em extrato de Salix babylonica e Cyperus rotundus nas concentrações de 0, 10, 25, 50 e 100%, cada, e imersão em fertilizante comercial Forth®. Após 60 dias do plantio das estacas foram realizadas as avaliações de porcentagem de estacas enraizadas, número de raízes/estaca, número de brotações, número de folhas, número de estacas com brotações e massa seca das folhas. As sementes da espécie Pachira aquatica são dispersas com teor de água muito elevado (55%), e uma pequena redução nesse valor compromete sua qualidade fisiológica, permitindo caracterizar as sementes desta espécie como recalcitrantes. O aumento da concentração salina no substrato reduz a germinação e o vigor das sementes de P. aquatica, principalmente quando as sementes são submetidas a temperatura de 25 ºC. As sementes de P. aquatica são tolerantes a salinidade, sob temperatura de 30 ºC, com redução na germinação das sementes em concentrações acima da concentração de 6,0 dS.m-1. A P. aquatica é uma espécie de fácil enraizamento, não sendo necessário o uso de fitohormônio e fertilizante comercial Forth®. A aplicação de extratos de folhas de Cyperus rotundus e de Salix babylonica não se constitui uma alternativa viável na produção de mudas de P. aquatica.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Objetivou-se com este trabalho determinar a qualidade física e fisiológica de dez lotes de sementes de Acacia mangium Willd provenientes de plantios comerciais com diferentes idades estabelecidos na savana de Roraima. Os frutos foram coletados de plantios localizados na Serra da Lua, nos municípios do Cantá e Bonfim, de plantas com 4, 5, 7, 9 e 10 anos de idade. As sementes das cinco idades, após a determinação da massa de 1000 sementes, foram classificadas em pequenas e grandes, formando 10 lotes de sementes. O teste de germinação foi realizado, após a superação da dormência, em quatro repetições de 50 sementes, por lote, sobre papel de germinação e mantidos em gerbox a 25C. A embebição foi observada nos tempos 0, 1, 3, 5, 8, 12, 16, 24, 48, 60, 72, 96 e 120 horas para sementes colocadas entre papel. O teste de envelhecimento acelerado foi conduzido em gerbox, em quatro repetições de 50 sementes, mantidos em BOD a 41C por 0, 24, 48 e 72 horas. O teste de condutividade elétrica foi realizado com sementes sem e com a superação da dormência, em quatro repetições de 50 sementes imersas em 75 mL de água por 24 horas. As sementes de A. mangium não apresentam o padrão trifásico de absorção de água em 120 horas após a superação da dormência. Sementes pequenas de acácia, após a superação da dormência, absorvem mais água e apresentam maior média de porcentagem e velocidade de germinação inicial e menor tempo médio de germinação que sementes grandes. A exposição de sementes de A. mangium por 24 horas no envelhecimento acelerado reduz a porcentagem e velocidade de germinação e aumenta a porcentagem de sementes mortas e de plântulas anormais. A imersão das sementes em 75 mL de água por 24 horas a 25C resultam em valores de condutividade elétrica sem relação com a germinação. A idade da planta não apresenta relação com a massa de 1000 sementes e com a absorção de água em 120 horas, para sementes submetidas à superação da dormência. Sementes de plantas com 10 anos apresentam maior porcentagem e velocidade de germinação que sementes de plantas com 4 anos de idade. / The objective of this work was determinate the physic and physiologic quality of ten lots of Acacia mangium Willd. from different commercial established plant ages in Roraimas savanna. Fruits were collected from plantations in Serra da Lua, in Cantá and Bonfim, from plants with 4, 5, 7, 9 and 10 years-old. Seeds from five plant ages, after the determinations of 1000 seeds weight, were classified in small and large, composing 10 lots. Germination test has been done, after dormancy overcoming, in four repetitions with 50 seeds, per lot, above germination paper and inside gerbox in 25C. The imbibition was observed in the times 0, 1, 3, 5, 8, 12, 16, 24, 48, 60, 72, 96 and 120 hours to seeds put between papers. The Seed aging test was made in gerbox in four repetitions with 50 seeds, maintained in BOD in 41C for 0, 24, 48 and 72 hours. The electrical conductivity test was made to seeds without and with dormancy overcoming, in four repetitions with 50 seeds immersed in 75 mL of water for 24 hours. Seeds of A. mangium do not exhibit the three-stage water absorption process in 120 hours, after dormancy overcoming. Small seeds of acacia, after dormancy overcoming, absorb more water and show higher mean of percentage and speed of initial germination and lower time mean of germination than large seeds. Exposition the A. mangium seeds for 24 hours in seed age test reduces the percentage and speed of germination and increases the percentages of dead seeds and abnormal seedlings. The immersion of the seeds in 75 mL of water for 24 hours in 25C results in value of electrical conductivity with no relation to germination. The plant age do not show relation to 1000 seeds weight and to water absorption process for 120 hours, from seeds submitted to dormancy overcoming. Seeds from plants with 10 years-old show higher percentage and speed of germination than seeds from plants with 4 years-old.

Nessa pesquisa foi avaliada a utilização do sal de tetrazólio para determinar a maturidade fisiológica das sementes de milho. As sementes utilizadas foram dos híbridos Pioneer 4285 e Dow 2B587, semeadas em 03/10/2014 e 05/12/2014 respectivamente, e colhidas a partir dos 40 dias após o florescimento (DAF), com intervalos de 4 dias até os 68 DAF. As sementes colhidas foram avaliadas quanto à viabilidade e ao vigor (testes de germinação, de emergência da plântula, de condutividade elétrica, de envelhecimento acelerado e determinações do comprimento da plântula). Os parâmetros utilizados para determinar o ponto de maturidade fisiológica das sementes foram a camada preta, a linha de leite, a massa de matéria seca, o teor de água e a avaliação dos tecidos da semente utilizando o sal de tetrazólio, utilizando o método descrito para avaliar a viabilidade, complementado pela avaliação da atividade das células da chalaza e da zona de transferência do endosperma para o embrião. Para as sementes de milho dos dois híbridos a germinação foi superior a 95% e não houve diferença entre as épocas de colheita, somente nas últimas colheitas das sementes do híbrido Dow 2B587 houve redução da germinação e do vigor. O ponto de maturidade fisiológica (PM) foi identificado aos 56 DAF para as sementes de milho do híbrido P4285 e aos 48 DAF para as do híbrido Dow 2B587 e correspondeu ao estádio 4 da linha de leite e ao máximo de acúmulo da matéria seca. O máximo de vigor foi detectado por meio do resultado do teste de envelhecimento acelerado oito dias antes do (PM) para os dois híbridos. A atividade das células do endosperma está relacionada com os demais indicadores do PM (linha de leite, camada preta, massa de matéria seca e teor de água). O transporte de fotoassimilados da planta mãe para a semente cessa no ponto de maturidade fisiológica da semente, desativando o transporte no qual atuam as células da chalaza e da região basal do endosperma. A utilização do sal de tetrazólio possibilita identificar a morte das células da região basal do endosperma, uma vez que a partir desse momento não há mais a reação dessas células com o sal de tetrazólio, indicando que não têm atividade celular. Dessa forma, é possível caracterizar o ponto de maturidade fisiológica da semente de milho, por meio da atividade do sal de tetrazólio; essa caracterização é confirmada pela expressão das enzimas CAT e MDH. / In this study were evaluated the use of the tetrazolium salt to determine corn seed physiological maturity. The seeds used were the hybrids 4285 Pioneer and Dow 2B587, planted on 10.03.2014 and 05.12.2014 respectively, and harvested after 40 days after flowering (DAF), with 4-day intervals until 68 DAF. The harvested seeds were evaluated for viability and vigor (germination test, seedling emergence, electrical conductivity test, accelerated aging test and seedling length). The parameters used to determine the seeds physiological maturity were the black layer, the milk line, the seed dry matter, seed water content and the evaluation of seed tissues using the tetrazolium salt, method to assess seed viability associated to the evaluation of chalaza cells the endosperm cells. The seeds corn germination, both hybrids, was greater than 95% and there is no difference between harvest times. Corn seed physiological maturity (PM) was identified at 56 DAF for both hybrids, P4285 and 48 DAF for hybrid Dow 2B587 and corresponded to stage 4 of the milk line and the accumulation of maximum dry matter. The maximum vigor was detected by accelerated aging test eight days before PM, for the two seed hybrids. The activity of endosperm cells is related to the other PM indicators (milk line, black layer, dry matter and water content). The transport of the nutrients from plant to the seed ceases at the seed physiological maturity, disabling the transport through chalaza cells and basal area. The use of the tetrazolium salt allows identifying the cell death of basal region, since from that time no further reaction of these cells as the tetrazolium salt indicating that these do not already have cell activity. This parameter corresponds to the others evaluated, thus demonstrating that the tetrazolium salt is effective for corn seed physiological maturity characterization.

O tratamento industrial de sementes é utilizado para, aproximadamente, 100% das sementes híbridas de milho comercializadas no Brasil. Assim, é essencial verificar se a aplicação de produtos químicos nas sementes de milho interfere nos resultados das análises destas sementes. Portanto, nesta pesquisa foi comparada a germinação das sementes híbridas de milho de três cultivares classificadas em peneiras de crivo circular e oblongo, em função da aplicação de produtos químicos (fungicida, inseticida, nematicida e polímero) em relação às sementes sem tratamento químico (Controle). Para complementar a determinação da qualidade das sementes foram avaliados o teor de água das sementes, o comprimento médio da raiz da plântula, a emergência da plântula e o vigor. As análises foram realizadas no Departamento de Produção Vegetal da Escola Superior de Agricultura \"Luiz de Queiroz\", Universidade de São Paulo. O teor de água foi determinado pelo método da estufa a 105 ± 3 °C, por 24 horas. Para o teste de germinação foram utilizados o substrato papel (RP), quatro repetições de 50 sementes ou oito repetições de 25 sementes e as avaliações entre o 3º e o 7º dia após a instalação do teste. Os tratamentos com fungicida, inseticida e nematicida não interferiram no teor de água das sementes de milho, independentemente do genótipo e da forma das sementes. Os resultados do teste de germinação das sementes de milho foram analisados, estatisticamente e utilizando as Tabelas de Tolerância das Regras para Análise de Sementes, e é possível verificar que o tratamento industrial das sementes não interfere nos resultados do teste de germinação, conforme proposto nas atuais Regras para Análise de Sementes. No teste de germinação, é possível avaliar a germinação das sementes de milho no 3º dia após a instalação do teste, para antecipar a obtenção dos resultados. A colocação de 25 sementes de milho no substrato papel (RP) favorece a avaliação do desenvolvimento da plântula no teste de germinação, em comparação à utilização de 50 sementes. / The seed industrial treatment is used to approximately 100% of the maize hybrids seeds marketed in Brazil. Thus, it is essential to verify if the application of chemical products in maize seeds interferes in the analysis results of these seeds. Therefore, in this research was compared maize seeds germination of three cultivars classified in circular and oblong screen sieves, depending on the application of chemical products (fungicide, insecticide, nematicide and polymer) in relation to the seeds without chemical treatment (Control). In order to complement the determination of seed quality, seed water content, seedling root mean length, seedling emergence and vigor were evaluated. The analysis were carried out in the Plant Production Department of the Luiz de Queiroz College of Agriculture, University of São Paulo. The water content was determined by the oven method at 105 ± 3 °C for 24 hours. In the germination test, the paper substrate (RP), four replicates of 50 seeds or eight replicates of 25 seeds were used and the evaluations between the 3rd and the 7th day after of the test installation. The treatments with fungicide, insecticide and nematicide did not interfere in the water content of the maize seeds, independently of the genotype and the seeds shape. The results of the maize seeds germination test were statistically analyzed and using the Tolerance Tables of the Rules for Seed Testing and it is possible to verify that the seed industrial treatment does not interfere in the results of the germination test, as proposed in the current Rules for Seed Testing. In the germination test, it is possible to evaluate the maize seeds germination on the 3rd day after the test installation, in order to anticipate the results. The placement of 25 maize seeds on the paper substrate (RP) favors the evaluation of the seedling development in the germination test, compared to the use of 50 seeds.