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Made available in DSpace on 2016-04-28T14:58:57Z (GMT). No. of bitstreams: 1 2005-Marta Bruno Loureiro.pdf: 2008902 bytes, checksum: 98c5d8a1e29a820780c9fe727ebed874 (MD5) Previous issue date: 2005-08-29 / Funda??o Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / Apuleia leiocarpa is a forestall specie commonly known as grapia and garapa. Its trees are widely spread over Brazilian territory occurring more specifically on rain forest formations with seasonal semidecidious characteristics. Garapa seeds are an important source of medicinal substances as well as used for ornamental and environmental recovery purposes. It has been used on both tanning and timber industry and notably its natural populations have deeply decreased its growth due to massive exploitation. In this context, this work aimed to evaluate the development of A. leiocarpa seeds during the maturation phase. Researches were conducted for two successive crop years (2002 and 2003) and also analyzed seeds performance under specific storage conditions and the physiological quality of seeds. This scientific study results might be used as database information to guide the elaboration of specie s preservation proposals. Research samples were collected at Tingu? Biological Reserve, state of Rio de Janeiro, Brazil and biological analysis and tests were performed at Seeds Analysis Laboratory of Universidade Federal Rural do Rio de Janeiro at Serop?dica city, Brazil. This work results concludes that A. leiocarpa seeds physiological maturity was achieved within 98 days after anthesis (98DAA) in 2002. In 2003 it was not able to objectively determine the seeds maturity cycle. Seeds harvests are recommended as soon as fruits aspect changes from green-yellow to brown color combined with a higher proportion of brown seeds availability. The most efficient technique to overcome seed dormancy was the use of immersion treatment into concentrated sulphuric acid during 20 minutes. It was not observed any influence of either testa color or its size on A. leiocarpa seed germination process. The use of half-permeably packaging (polyethylene bags) under a nominal temperature of 18?C and 50% relative humidity was considered the most appropriate storage condition to A. leiocarpa seeds. / Apuleia leiocarpa ? uma esp?cie florestal, conhecida como gr?pia e garapa, que apresenta ampla distribui??o geogr?fica no territ?rio brasileiro, ocorrendo na mata atl?ntica, nas forma??es caracter?sticas da Floresta Estacional Semidecidual. A esp?cie apresenta import?ncia na industria madeireira e de curtume, possui indica??es de uso medicinal, ornamental e em plantios para recupera??o ambiental. No entanto, foi extra?da de forma maci?a, e suas popula??es naturais sofreram diminui??o significativa. Diante desta situa??o, os objetivos deste trabalho foram acompanhar a matura??o das sementes de Apuleia leiocarpa em dois anos de produ??o (2002 e 2003), avaliar o comportamento das sementes durante o armazenamento e analisar os fatores intr?nsecos ?s sementes que afetam sua qualidade fisiol?gica, a fim de gerar informa??es que possam nortear a elabora??o de propostas para a conserva??o da esp?cie. As coletas foram realizadas na Reserva Biol?gica do Tingu?, RJ e os ensaios conduzidos no Laborat?rio de An?lise de Sementes da Universidade Federal Rural do Rio de Janeiro, Serop?dica, RJ. Com base nos resultados obtidos pode-se concluir que a maturidade fisiol?gica das sementes de Apuleia leiocarpa foi atingida aos 98 DAA no ano de 2002 e n?o pode ser determinada em 2003. ? recomend?vel que a coleta de sementes seja realizada a partir do momento em que ocorre a mudan?a de colora??o dos frutos de verdeamarelo para marrom, juntamente com aparecimento da maior propor??o de sementes com colora??o marrom A escarifica??o com ?cido sulf?rico concentrado por vinte minutos, foi considerado o tratamento mais indicado para a supera??o da dorm?ncia de sementes. Nem o tamanho das sementes, nem a colora??o do tegumento influenciaram a porcentagem de germina??o de sementes de Apuleia leiocarpa. . A embalagem semiperme?vel sob c?mara seca (18?C e U.R. de 50%), foi considerada a condi??o mais adequada para a conserva??o de sementes de Apuleia leiocarpa.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Cultivars of maize landraces provide the farmer seed production with high genetic variability, resistance and wide adaptation, beyond the advantage that the farmer can select them and store them for use next season, without the purchase of inputs. However, due to the high genetic variability, standardized tests to determine the physiological quality of the seeds need to be adapted so that they can be applied to the Land varieties. Therefore, this study aims at evaluating different methodologies for evaluation of physiological and sanitary quality for growing maize landraces. We used seeds produced by farmers Seed Guardians of Creole Ibarama - RS. We evaluated the effect of these seeds (using various tests) and sanitary quality (for both methods of detection). Moreover, there was monitoring the process of seed maturation in different harvest periods. The germination test showed variations between the evaluation periods and different temperatures tested, and that the temperature of 25 º C and 6 º day of evaluation, we obtained the highest percentage of germination, for most cultivars. In cold test response variability occurred when the cultivars analyzed at different temperatures and exposure times. The pH of the exudate tests showed no significant difference between the variations tested methodologies. Land varieties for the tetrazolium test can be performed with less concentration of tetrazolium salt (0.07%). The point of harvest, as the physiological quality showed better results in the period was 20 to 30% moisture (held last harvest) and fungal incidence ranged between periods of maturation evaluated. / As cultivares crioulas de milho proporcionam ao agricultor a produção de sementes com alta variabilidade genética, ampla resistência e adaptação, além da vantagem de que próprio agricultor pode selecioná-las e armazená-las para utilização na próxima safra, sem necessidade da compra do insumo. Porém, devido a essa grande variabilidade genética, os testes padronizados para determinação da qualidade fisiológica das sementes necessitam ser adaptados para que possam ser aplicados as cultivares crioulas. Diante disso, esse trabalho tem como objetivo geral avaliar diferentes metodologias de análise da qualidade fisiológica e sanitária e estabelecer o ponto ideal de colheita; para cultivares crioulas de milho. Foram utilizadas sementes produzidas pelos agricultores Guardiões de Sementes Crioulas de Ibarama RS. Avaliou-se o vigor destas sementes (por meio de diferentes testes) e a qualidade sanitária (por dois métodos de detecção). Além disso, realizou-se o acompanhamento do processo de maturação das sementes em diferentes períodos de colheita. O teste de germinação apresentou variações entre os períodos de avaliação e as diferentes temperaturas testadas, sendo que, na temperatura de 25ºC e ao 6º dia de avaliação, obteve-se o maior porcentual de germinação, para maioria das cultivares. No teste de frio ocorreu variabilidade de resposta das cultivares quando analisadas em diferentes temperaturas e períodos de exposição. O testes de pH do exsudato não apresentou diferença significativa entre as variações de metodologias testadas. Para as cultivares crioulas o teste de tetrazólio pode ser realizado com menor concentração de sal de tetrazólio (0,07%). Os métodos de avaliação da qualidade sanitária não apresentaram diferenças significativas entre si, porém a metodologia através do papel filtro é mais adequada pela facilidade e rapidez de execução. O ponto de colheita, quanto a qualidade fisiológica apresentou melhores resultados, foi no período com 20% a 30% de umidade (última colheita realizada) e a incidência fúngica variou entre os períodos de maturação avaliados.

Submitted by Bárbara Panoff Valário (barbarapanoff@yahoo.com.br) on 2016-10-07T21:14:48Z No. of bitstreams: 1 Tese correções definitivo setembro 2016.pdf: 3127741 bytes, checksum: d6857da82fb09539bd86f7e77346f4eb (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-10-11T14:05:55Z (GMT) No. of bitstreams: 1 valario_bp_dr_bot.pdf: 3127741 bytes, checksum: d6857da82fb09539bd86f7e77346f4eb (MD5) / Made available in DSpace on 2016-10-11T14:05:55Z (GMT). No. of bitstreams: 1 valario_bp_dr_bot.pdf: 3127741 bytes, checksum: d6857da82fb09539bd86f7e77346f4eb (MD5) Previous issue date: 2016-08-12 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Não existe consenso sobre qual o estádio de desenvolvimento que a tolerância à dessecação e longevidade são adquiridos em sementes de soja e quais proteínas estão associadas com estes eventos. Portanto, o presente trabalho teve o objetivo caracterizar a aquisição da tolerância à dessecação e longevidade em sementes de soja e identificar proteínas associadas. O estudo foi realizado na Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP), Faculdade de Ciências Agronômicas-UNESP-Botucatu em parceria com o Centro Virtual de Toxicologia (CEVAP), Campus de Botucatu-SP e com o Laboratório de Sementes Florestais da Universidade Federal de Lavras (UFLA). As sementes foram produzidas na safra 2013/2014 seguida da coleta e caracterização morfofisiológica (caracterização visual, germinação e teor de água) das sementes nos estádios reprodutivos R5.1, R5.2, R5.3, R5.4, R5.5, R6, R7.1, R7.2, R7.3, R8.1, R8.2, R8.3 e R9. Posteriormente, realizou-se a determinação do teor de água, matéria seca e fresca das sementes. Em seguida, as sementes foram secas e armazenadas de 5 a 85 dias à 35°C e 75% umidade relativa (UR), para caracterizar a aquisição de longevidade. Para tolerância à dessecação, as sementes foram secas em gerbox contendo carbonato de potássio à 42% de umidade e 35°C até 0.10g água por grama de massa seca. Para se conhecer o perfil proteômico, foram extraídas proteínas de cada estádio de desenvolvimento, separadas em fitas de pI e géis de acrilamida e analisados no ImageMaster Platinum 7.0. Os spots significativos e exclusivos de cada estádio foram recortados e analisados por espectrometria de massas ESI-QToF. Foram sequenciadas e identificadas 167 proteínas, sendo que trinta e cinco tiveram a expressão diferencial ao longo da fase tardia da maturação. A tolerância à dessecação foi adquirida no estádio R7.2, porém a longevidade foi adquirida em estádios fenológicos posteriores. As proteínas LEAs MAT1, SBP65 e MP2 estão relacionadas com tolerância à dessecação e as pertencentes ao grupo 3 (51 kDa, SBP65 e MP2) juntamente com a MAT9 e algumas LEAs do grupo 5 (Small hydrophilic plant seed protein) estão relacionadas com aquisição de longevidade. / There is no consensus regarding when desiccation tolerance and longevity are acquired in soybean seeds. Therefore, this study aimed at to characterize the acquisition of desiccation tolerance and longevity in soybean seeds and identify proteins associated. The study was performed at the Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Colegue of Agricultual Science-UNESP-Botucatu in collaboration with the Virtual Center for Toxicology (CEVAP), Botucatu-SP and with the Forest Seeds Laboratory at the Federal University of Lavras (UFLA). Seed production was carried out in the crop year 2013/2014 followed by the collection and characterization of seeds at the reproductive stages R5.1, R5.2, R5.3, R5.4, R5.5, R6, R7.1, R7.2, R7.3, R8.1, R8.2, R8.3 and R9. Subsequently, it was performed the determination of water content, dry and fresh weight of the seeds. Then, seeds were dried and stored at 35 °C and 75% relative humidity (RH), to characterize the acquisition of longevity. To know the proteomic profile, proteins were extracted from each stage of development, separated in acrylamide gels and analyzed by ImageMaster Platinum 7.0. The significant spot and unique to each stadium were cut and analyzed by mass spectrometry ESI-QTOF mass. They were sequenced and identified 167 proteins, and thirty-five had the differential expression along the late stage of maturation. The desiccation tolerance was acquired at the stage R7.2 but longevity was acquired at later during seed development. Proteins LEAs MAT1, SBP65 and MP2 are related to desiccation tolerance and those belonging to group 3 (51 kDa, SBP65 and MP2) together with MAT9 and some LEAs group 5 (Small hydrophilic plant seed protein) are related to acquisition of longevity. / FAPESP: 2014/14638-0

<p>The B3-domain transcription factor ABI3 is a major regulator of gene expression of seed maturation during Arabidopsis embryogenesis. The <i>napA</i> gene encodes for a <i>Brassica napus</i> 2S storage protein specifically expressed in the embryo during the early and mid-maturation phase (MAT program).The <i>napA</i> promoter contains two essential cis-sequences; the B-box, which functions as an Abscisic acid-responsive element (ABRE) and the RY/G cluster. ABI3 is known to target both these cis-sequences. Several bZIP factors expressed during seed maturation, bZIP12, bZIP38 and bZIP66, as well as a heterodimer of ABI5 and bZIP67, can bind the B-box ABRE in a yeast one-hybrid assay. Amongst them ABI3 and bZIP67 are able to activate synergistically the two cis-elements in a transient protoplast assay. We also show that bZIP67 interacts directly with ABI3 in a yeast two-hybrid assay. Therefore, we hypothesize that i)ABI3 is recruited indirectly to <i>napA</i> through molecular interaction with bZIP67 bound to the B-box ABRE, ii) ABI3 binds directly to the RY-element and interacts with bZIP67 targeted to the adjacent G-box found in the napA RY/G-cluster.</p><p>We also show that the RY/G cluster is responsible for repression of <i>napA</i> expression during the late maturation LEA program, and for repression of ABI3-mediated transactivation during germination. ABI3 from which the A1 activation domain had been removed, can bind to the <i>napA</i> RY-element in a yeast one-hybrid assay, in contrast to full-length ABI3, suggesting that ABI3 DNA-binding abilities are regulated by auto-inhibition. We propose that during late maturation ABI3 loses ability to bind RY, which results in repression of MAT genes but not of LEA genes that contain fewer RY-elements. In parallel, we show that the B3-domain VAL proteins bind to RY-elements and decrease ABI3-mediated transactivation of the <i>napA</i> RY/G and therefore act as active repressors maintaining silencing of MAT genes during vegetative growth.</p>

Os objetivos dessa pesquisa foram avaliar as alterações de natureza física, fisiológica e bioquímica durante a formação das sementes de soja, produzidas nos anos 2009 e 2010, em Piracicaba, São Paulo. Foram utilizadas sementes de dois cultivares de soja, CD - 202 e CD - 224, e os tratamentos foram compostos pelos momentos de colheita, ao longo do processo de formação das sementes, e pela utilização ou não da secagem artificial. Para as avaliações foram determinados os número de dias para a emergência da plântula, para a floração, para a floração plena, para a colheita, os parâmetros físicos (produtividade, teor de água das sementes e massa de mil sementes) fisiológicos (viabilidade e vigor) e bioquímicos (teores de óleo, de proteína, de clorofila, carotenoides, de lignina e de carboidratos). O delineamento experimental utilizado foi em blocos ao acaso, em que cada bloco continha uma unidade experimental de cada cultivar, distribuída de forma casualizada, em esquema fatorial de onze (momentos de colheita) x dois (sem secagem e com secagem), com quatro repetições e as análises estatísticas foram realizadas com o software R. Foi possível concluir que na maturidade fisiológica das sementes de soja, estádio R7, independentemente do cultivar e da avaliação das sementes úmidas ou secas, a produtividade, a viabilidade e os teores de lignina são máximos; No momento de colheita das sementes de soja, estádio R9, independentemente do cultivar e da avaliação de sementes úmidas ou secas, o acúmulo de massa é máximo, há a redução do teor de água, da viabilidade e do vigor e a semente tem mais óleo e proteína; O vigor das sementes é máximo no estádio R7 para as sementes avaliadas secas e no estádio R8 para as avaliadas úmidas, independentemente do cultivar; Há a degradação completa da clorofila nos estádios R7, para as sementes do cultivar CD - 202, e R8, para as sementes do cultivar CD - 224; Há carotenoides em todos os estádios de desenvolvimento da semente de soja, porém há mais carotenoides no início do processo de formação das sementes; Há variação da quantidade de carboidratos em função da avaliação das sementes úmidas ou secas. / This experiment aimed at the evaluation of the physical, physiological and biochemical changes during formation of soy seeds, produced in 2009 and 2010, in Piracicaba, São Paulo. Seeds of two cultivars of soy were used, namely CD - 202 and CD - 224, and treatments were composed by the moment of harvest, along the process of formation of seeds, and by the use or non-use of artificial drying. For the evaluations, we determined the number of days for seedling emergency, flowering, full flowering, harvest, physical parameters (productivity, rate of water in the seeds and mass of a thousand seeds) physiological parameters (viability and vigor) and biochemical parameters (rate of oil, of protein, of chlorophyll, of lignin and carbohydrates). The experimental delineation in use was in random blocks, in which each block contained one experimental unit of each cultivar, distributed at random, in a factorial scheme of eleven (harvesting periods), x two (dried and not dried), at four repetitions, and the statistical analysis were performed with software R. It was possible to conclude that at physiological maturity of soy seeds, stage R7, independently of the cultivar and of the evaluation of dry or humid seeds, the productivity, viability and rates of lignin are at their maximum; In the moment of harvest of soy seeds, stage R9, independently of the cultivar and evaluation of humid or dry seeds, the accumulation of mass is at its maximum, there is a drop in the level of water, of the viability and vigor, and the seed contains more oil and protein; The vigor of the seeds is at its maximum at stage R7 for the seeds which were evaluated dry and at stage R8 for the ones evaluated as humid, independently of the cultivar; There is the complete deterioration of the chlorophyll at stages R7, for the seeds of cultivar CD - 202 and R8, for the seeds of cultivar CD - 224; There are carotenoids in all stages of development of soy seed, however there are more of them in the beginning of the process of formation of seeds. There is variation of quantity of carbohydrates according to the evaluation of humid or dry seeds.

The B3-domain transcription factor ABI3 is a major regulator of gene expression of seed maturation during Arabidopsis embryogenesis. The napA gene encodes for a Brassica napus 2S storage protein specifically expressed in the embryo during the early and mid-maturation phase (MAT program).The napA promoter contains two essential cis-sequences; the B-box, which functions as an Abscisic acid-responsive element (ABRE) and the RY/G cluster. ABI3 is known to target both these cis-sequences. Several bZIP factors expressed during seed maturation, bZIP12, bZIP38 and bZIP66, as well as a heterodimer of ABI5 and bZIP67, can bind the B-box ABRE in a yeast one-hybrid assay. Amongst them ABI3 and bZIP67 are able to activate synergistically the two cis-elements in a transient protoplast assay. We also show that bZIP67 interacts directly with ABI3 in a yeast two-hybrid assay. Therefore, we hypothesize that i)ABI3 is recruited indirectly to napA through molecular interaction with bZIP67 bound to the B-box ABRE, ii) ABI3 binds directly to the RY-element and interacts with bZIP67 targeted to the adjacent G-box found in the napA RY/G-cluster. We also show that the RY/G cluster is responsible for repression of napA expression during the late maturation LEA program, and for repression of ABI3-mediated transactivation during germination. ABI3 from which the A1 activation domain had been removed, can bind to the napA RY-element in a yeast one-hybrid assay, in contrast to full-length ABI3, suggesting that ABI3 DNA-binding abilities are regulated by auto-inhibition. We propose that during late maturation ABI3 loses ability to bind RY, which results in repression of MAT genes but not of LEA genes that contain fewer RY-elements. In parallel, we show that the B3-domain VAL proteins bind to RY-elements and decrease ABI3-mediated transactivation of the napA RY/G and therefore act as active repressors maintaining silencing of MAT genes during vegetative growth.

Os objetivos dessa pesquisa foram avaliar as alterações de natureza física, fisiológica e bioquímica durante a formação das sementes de soja, produzidas nos anos 2009 e 2010, em Piracicaba, São Paulo. Foram utilizadas sementes de dois cultivares de soja, CD - 202 e CD - 224, e os tratamentos foram compostos pelos momentos de colheita, ao longo do processo de formação das sementes, e pela utilização ou não da secagem artificial. Para as avaliações foram determinados os número de dias para a emergência da plântula, para a floração, para a floração plena, para a colheita, os parâmetros físicos (produtividade, teor de água das sementes e massa de mil sementes) fisiológicos (viabilidade e vigor) e bioquímicos (teores de óleo, de proteína, de clorofila, carotenoides, de lignina e de carboidratos). O delineamento experimental utilizado foi em blocos ao acaso, em que cada bloco continha uma unidade experimental de cada cultivar, distribuída de forma casualizada, em esquema fatorial de onze (momentos de colheita) x dois (sem secagem e com secagem), com quatro repetições e as análises estatísticas foram realizadas com o software R. Foi possível concluir que na maturidade fisiológica das sementes de soja, estádio R7, independentemente do cultivar e da avaliação das sementes úmidas ou secas, a produtividade, a viabilidade e os teores de lignina são máximos; No momento de colheita das sementes de soja, estádio R9, independentemente do cultivar e da avaliação de sementes úmidas ou secas, o acúmulo de massa é máximo, há a redução do teor de água, da viabilidade e do vigor e a semente tem mais óleo e proteína; O vigor das sementes é máximo no estádio R7 para as sementes avaliadas secas e no estádio R8 para as avaliadas úmidas, independentemente do cultivar; Há a degradação completa da clorofila nos estádios R7, para as sementes do cultivar CD - 202, e R8, para as sementes do cultivar CD - 224; Há carotenoides em todos os estádios de desenvolvimento da semente de soja, porém há mais carotenoides no início do processo de formação das sementes; Há variação da quantidade de carboidratos em função da avaliação das sementes úmidas ou secas. / This experiment aimed at the evaluation of the physical, physiological and biochemical changes during formation of soy seeds, produced in 2009 and 2010, in Piracicaba, São Paulo. Seeds of two cultivars of soy were used, namely CD - 202 and CD - 224, and treatments were composed by the moment of harvest, along the process of formation of seeds, and by the use or non-use of artificial drying. For the evaluations, we determined the number of days for seedling emergency, flowering, full flowering, harvest, physical parameters (productivity, rate of water in the seeds and mass of a thousand seeds) physiological parameters (viability and vigor) and biochemical parameters (rate of oil, of protein, of chlorophyll, of lignin and carbohydrates). The experimental delineation in use was in random blocks, in which each block contained one experimental unit of each cultivar, distributed at random, in a factorial scheme of eleven (harvesting periods), x two (dried and not dried), at four repetitions, and the statistical analysis were performed with software R. It was possible to conclude that at physiological maturity of soy seeds, stage R7, independently of the cultivar and of the evaluation of dry or humid seeds, the productivity, viability and rates of lignin are at their maximum; In the moment of harvest of soy seeds, stage R9, independently of the cultivar and evaluation of humid or dry seeds, the accumulation of mass is at its maximum, there is a drop in the level of water, of the viability and vigor, and the seed contains more oil and protein; The vigor of the seeds is at its maximum at stage R7 for the seeds which were evaluated dry and at stage R8 for the ones evaluated as humid, independently of the cultivar; There is the complete deterioration of the chlorophyll at stages R7, for the seeds of cultivar CD - 202 and R8, for the seeds of cultivar CD - 224; There are carotenoids in all stages of development of soy seed, however there are more of them in the beginning of the process of formation of seeds. There is variation of quantity of carbohydrates according to the evaluation of humid or dry seeds.

La phase de maturation des graines est caractérisée par l’ac-quisition successive de composantes qui constituent la qua-lité physiologique d’un lot de semences, à savoir la toléranceà la dessiccation (capacité à survivre au retrait total de l’eaucellulaire), la longévité (capacité de survivre à l'état sec pen-dant le stockage), la dormance ainsi que la vigueur germina-tive (capacité à germer de façon rapide et homogène quelquessoient les conditions de l’environnement). La production desemences à haute qualité germinative représente un enjeumajeur pour les semenciers car elle constitue un levier clefpour augmenter les rendements agricoles. Cependant, lesmécanismes régulant l’acquisition de la qualité germinativeet en particulier la longévité restent peu connus. Une étudepréalable d’un réseau de co-expression génique de facteursde transcription avait identifi é trois gènes candidats associésà la longévité chez Medicago truncatula :MtABL (ABA INSEN-SITIVE4-LIKE), MtABI5 (ABA INSENSITIVE5) et MtHSFA2.2(HEAT SHOCK FACTOR A2.2). L'objectif de cette thèse était devalider ces gènes et d’en comprendre leur fonction chez Medicagotruncatula et le pois par la caractérisation de mutantsd’insertion et EMS. ABL et ABI5 jouent un rôle dans la matu-ration en régulant positivement la longévité alors que celle-ci n’est pas affectée dans les mutants hsfa2.2. Des étudestranscriptomiques et biochimiques montrent que ABL et ABI5régulent de manière complexe la photosynthèse, la dégrada-tion de la chlorophylle et l’accumulation des oligosaccharide / Seed maturation is characterized by the acquisition ofthe various components that collectively constitute thephysiological quality or vigor of the seed: desiccation tolerance(DT, i.e. the capacity to survive complete drying), seedstorability or longevity (the capacity to remain alive duringstorage), dormancy, as well as fast and uniform germinationand seedling emergence under stressful conditions. Thesetraits are pivotal to ensure rapid and homogenous seedlingestablishment required for stable yield and are a majoreconomic challenge for the seed industry. Despite theiragronomic importance, the mechanisms regulating theiracquisition, including longevity, are still poorly understood. InMedicago truncatula, a gene co-expression network inferredthat transcription factors such asMtABL (ABA INSENSITIVE4-LIKE), MtABI5 (ABA INSENSITIVE5) and MtHSFA2.2 (HEATSHOCK FACTOR A2.2) are putative regulators of seedlongevity. The aim of this thesis was to characterize theirroles in Medicago truncatula and Pisum sativum using Tnt1insertion and EMS mutants. ABL and ABI5 are positiveregulators of longevity while defects in hsfa2.2 do not affectit. Transcriptomic and biochemical analyses show that ABLand ABI5 are involved in the regulation of photosynthesisassociated genes, chlorophyll loss and accumulation ofraffi nose family oligosaccharides (RFO). ABI5 is also involvedin the accumulation of stress proteins such as LEA proteins.By establishing a link between degreening, RFO contents andlongevity, our work offers new opportunities to tackle a