A l’heure où l’on cherche à optimiser les services éco-systémiques fournis par les prairies, une meilleure compréhension du fonctionnement des systèmes racinaires apparait comme nécessaire. Nous avons donc décidé de caractériser les stratégies d’espèces issues des familles des Fabaceae et Poaceae prairiales par la mesure de traits fonctionnels racinaires. Le principal résultat de ce travail est la mise en évidence de plusieurs axes majeurs de différentiation des stratégies racinaires et de leurs relations avec les exigences écologiques des espèces. Le plus important est le compromis entre stratégies de capture et de conservation des ressources. Les espèces à stratégie de capture sont mieux adaptées aux milieux peu stressants notamment pour l’eau, mais sont peu impactées par le manque de phosphore, ce sont aussi des compétitrices efficaces. Bien que les plantes à stratégie de conservation soient mieux à même de se développer dans des milieux continentaux, elles sont plus impactées que les autres par la présence de compétiteurs et le manque de phosphore. Le type de relations existant entre les stratégies aériennes et racinaires apparait aussi comme un marqueur de l’adaptation des plantes aux stress. L’étude du système racinaire est donc un moyen efficace de prédire le comportement des espèces de plantes prairiales face à des contraintes abiotiques et biotiques. Cela ouvre des perspectives particulièrement intéressantes notamment pour la construction de mélanges d’espèces mieux adaptées à leurs environnements. / In order to optimise grassland ecosystem services we need to improve our understanding of root system functioning. As a result, we decided to characterise strategies of species coming from grassland’ Fabaceae and Poaceae families, by root functional traits measurement. The main result of this work is the establishment of several axes of root strategies differentiation. The main axis is the trade-off between resources capture and conservation strategies. Species with capture strategies appear to be adapted to non-water stressful habitat and are barely impacted by phosphorus shortage; they also happen to be strong competitors. On the opposite, species with conservation strategies are adapted to water stressful continental climates, but are strongly impacted by phosphorus shortage and happen to be weak competitors. The kind of relation between above-ground and below-ground strategies also appears to be a marker of the plants adaptation to stress. We showed that the root system study is a good way to predict grassland species comportment to face abiotic and biotic constraints. The present work widens interesting perspectives for the sowing of mixed grassland species better adapted to their environments.

Triticeae Dumort. is a tribe within the Pooideae subfamily of Poaceae. Major crop genera found in this tribe include barley (Hordeum), wheat (Triticum) and rye (Secale) all of which are closely related to each other. In Turkey, with the several subgroups, this tribe is represented by 16 genera and 75 species, many of which have great economic values. The main objective of this research work is to determine the taxa of this tribe on the basis of their diagnostic anatomical characters of vegetative organs for the recognision of genera, sections, species, and infraspecific categories. By using both fresh and herbarium specimens, transverse sections of vegetative organs were obtained by using two different sectioning methods. This study covers both qualitative anatomical characters, such as sclerenchyma position, hair density and intercellular cavities of roots, shapes of leaves, presence of midrib, occurrence of leaf hairs, shapes of girders or strands, arrangement of sclerenchyma around vascular bundles and arrangement of epidermal cells, cell wall undulations, appearance of silica bodies, type of bulliform cells, arrangement of culm vascular bundles and their connections to the epidermis, hollowness of culms, as well as quantitative characters, such as sclerenchyma line number of roots, vascular bundle line numbers and diameters of culms, sclerenchyma line number of leaf margins, line numbers and sizes of all types of costal leaf hairs, stomata and interstomatal cell lines. In conclusion, all these properties are useful to understand both systematics and evolutionary relationships of the taxa. Moreover, the leaves of the tribe have the most numerous diagnostic characters. The roots do not have central metaxylem. The metaxylem elements are scattered in the vascular cylinder. The internodular parts of the culms may be hollowed or solid. However, the nodular parts of the culms generally have the same structure. Furthermore, there are two species which can be assigned as a subtribe.

The Triticeae is one of the most important tribes of the family Poaceae. It contains wheat (Triticum L.), barley (Hordeum L.) and rye (Secale L.) which are economically the most important cereals. Although the tribe has been the focus of several systematic studies there has not been a universally accepted taxonomic treatment for the tribe. This research study aiming to revise the tribe Triticeae Dumort. (Poaceae) in Turkey has been carried out by means of collecting specimens from all the localities in Turkey as well as examining the material collected over the years by the other researchers either from Turkey or abroad for a 4 year period starting from June 1th, 2006. All the specimens belonging the tribe were analysed by means of using standart taxonomic methods. This thesis is divided into four main chapters. In the first and second chapters, an introduction and general information about the tribe Triticeae and the material and methods used in the study are given. In the introduction part different taxonomic treatments on the tribe are explained briefly and the recent studies on the genera included in the tribe such as taxonomical, morphological and cytological are explained breifly. In the third chapter of the thesis, the significance of the morphological, micromorphological and ecological data which were used as diagnostic features in the taxonomy of the tribe are explained. Especially, SEM surveys of the glumes and lemma parts found to have great taxonomic values for the systematics of tribe. Distribution and habitat preferences of the tribe are discussed and IUCN threat categories of the taxa are reevaluated along with the types of threats so as to guarantee their sustainability of the rare taxa in Turkey. The fourth chapter covers the revision of the Tribe Triticeae in Turkey. A key for the genera is given. Synonymy, updated descriptions, flowering time, habitat, type citation, general distribution in Turkey, phytogeographical elements, specimen citations on a grid basis and general distribution outside Turkey, are given for each species. Along with general descriptions, keys to species and infraspecific categories are where necessary. In Tribe Triticeae, 18 genera, 79 species, 27 subspecies and 37 varieties have been recognized including 1 new species (Psathyrostachys narmanica Cabi &amp / Dogan sp. nov.), 3 new subspecies (Psathyrostachys fragilis (Boiss.) Nevski subsp. artvinense Cabi &amp / Dogan subsp. nov. / P. daghestanica (Alex.) Nevski subsp erzurumica Cabi&amp / Dogan subsp. nov. / Aegilops triuncialis L. subsp bozdagensis Cabi&amp / Dogan subsp nov.) and 4 new varieties (Agropyron cristatum (L.) subsp. pectinatum (Bieb.) Tzvelev var. mucranatum var. nov. / Eremopyrum bonaepartis (Sprengel) Nevski. var. aristatum Cabi &amp / Dogan / Thinopyrum pycnanthum (Godr.) Barkworth var. aristatum Cabi &amp / Dogan var. nov. / Hordeum spontaneum C. Koch var. anatolicum Cabi &amp / Dogan var. nov. In addition to the taxa new for science, Aegilops juvenalis (Thell.) Eig. and Hordeum spontaneum var. proskowetzii N&aacute / b

The plastid genomes of land plants are generally highly conserved in gene content and order, genome organization, and rates of sequence evolution; however, a few groups have experienced genomic change. The previously published sequence of Pelargonium X hortorum (Geraniaceae) reveals the largest, most rearranged plastid genome among land plants, and rate heterogeneity and genomic change have been documented in the monocot family Poaceae. Three initiatives were taken to characterize plastid genome evolution better in these groups. First, I estimate and compare genome-wide rates of sequence evolution in Geraniaceae genes relative to other angiosperms. An analysis of nucleotide substitutions for 72 plastid genes from 47 angiosperms, including nine Geraniaceae, shows that values of dN are accelerated in ribosomal protein and RNA polymerase genes. dN/dS, an indicator of selection, is significantly elevated in the same two classes of genes and ATPase genes. Second, I sequenced three additional Geraniaceae plastid genomes (Erodium texanum, Geranium palmatum, and Monsonia speciosa) and compare these sequences to each other, P. X hortorum, and other rosids. Geraniaceae plastid genomes are highly variable in size, gene content and order, and base composition. The genome of M. speciosa is among the smallest land plant plastid genomes, and one copy of the IR region in E. texanum has been lost. Gene/intron loss and gene duplication are rampant in Geraniaceae plastid genomes, and a number of losses are phylogenetically inconsistent. To explain the unusual rates and patterns of genome evolution in Geraniaceae, I propose a model of aberrant DNA repair coupled with altered gene expression. Lastly, I characterize genome evolution in the family Poaceae and order Poales. There has been a recent surge in the availability of Poaceae sequences, but a comprehensive analysis of genome evolution had not been performed that included any non-grass Poales taxa. I present the sequence of Typha latifolia (Typhaceae), the first non-grass Poales sequenced to date, and I show that Poaceae plastid genomes exhibit increased genomic rearrangements and nucleotide substitutions. These analyses show the extent of lineage-specific rate acceleration on the branch leading to Poaceae and deceleration during the diversification of the family. / text

Th.--Méd.--Nancy 1, 1983. N°: 197.

Made available in DSpace on 2014-06-11T19:27:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-12-14Bitstream added on 2014-06-13T19:55:46Z : No. of bitstreams: 1 parra_fbg_me_araca.pdf: 449639 bytes, checksum: c51e2b8791999e7a56d0bc1fad648826 (MD5) / O objetivo do trabalho foi analisar o Ajifer L40 como fonte alternativa de fertilizante nitrogenado na produção de matéria seca, nutrientes da folha e atributos químicos do solo da Brachiaria brizantha cv. Xaraés (capim-Xaraés). O experimento foi conduzido em área do Sindicado Rural no município de Araçatuba, localizado na região da Alta Noroeste do Estado de São Paulo, no período de outubro de 2005 a maio de 2009 em solo classificado como Latossolo Vermelho Amarelo. O delineamento experimental foi em blocos casualizados com 10 tratamentos e três repetições. Os tratamentos foram arranjados em esquema fatorial 3 x 3 + 1, sendo três doses de nitrogênio (100, 200 e 400 kg ha-1 ano-1) e três fontes (uréia, sulfato de amônio e Ajifer L40) e um tratamento adicional (testemunha com dose 0 de N). Os fertilizantes apresentaram resposta máxima média dos quatro anos de avaliação na dose de 322 kg ha-1 de N. O teor de proteína bruta na parte aérea do capim-Xaraés foi linearmente crescente até a dose de 400 kg ha-1 de N para as três fontes estudadas. O Ajifer L40 e o sulfato de amônio foram importante fonte de enxofre para a nutrição das plantas. As fontes nitrogenadas Ajifer L40 e sulfato de amônio apresentaram comportamento semelhante, proporcionando maior acidez na camada superficial do solo em relação à fonte uréia. A utilização dos fertilizantes Ajifer L40, sulfato de amônio e uréia não alterou a concentração de sódio e a condutividade elétrica no solo. A fonte alternativa Ajifer L40 é similar às outras fontes de fertilizantes convencionais / The aim was to evaluate the Ajifer L40 as an alternative source of nitrogen fertilizer on dry matter production, leaf nutrients and soil chemical properties of Brachiaria brizantha cv. Xaraés (Xaraés-grass). The experiment was conducted in Syndicate Rural area in the municipality of Araçatuba, located in Upper Northwest of São Paulo, from October 2005 to May of 2009 in a soil classified as Latosol Yellow Red. The experimental design was randomized blocks with 10 treatments and three replications. The treatments were arranged in a 3 x 3 + 1, three nitrogen levels (100, 200 and 400 kg ha-1 yr-1) and three sources (urea, ammonium sulfate and Ajifer L40) and an additional treatment (control dose of 0 N). Fertilizers showed a mean maximum of four years of evaluation at a dose of 322 kg ha-1 N. The crude protein content in leaves of Xaraés-grass was increasing linearly with doses up to 400 kg ha-1 of N for the three sources studied. The Ajifer L40 and ammonium sulfate were an important source of sulfur for plant nutrition. The nitrogen sources, Ajifer L40 and ammonium sulfate were similar, providing greater acidity in the topsoil is in relation to urea. The use of fertilizers Ajifer L40, ammonium sulfate and urea did not alter the concentration of sodium and electrical conductivity in the soil. The alternative source Ajifer L40 is similar to other conventional sources fertilizers

Submitted by Haroudo Xavier Filho (haroudo.xavierfo@ufpe.br) on 2016-04-22T16:55:34Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertacao_SheylaSilvaLima_2015.pdf: 4958893 bytes, checksum: 21511e1c9e1a86ea210befeb33c91543 (MD5) / Made available in DSpace on 2016-04-22T16:55:34Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertacao_SheylaSilvaLima_2015.pdf: 4958893 bytes, checksum: 21511e1c9e1a86ea210befeb33c91543 (MD5) Previous issue date: 2015-02-24 / FACEPE / Ciclotídeos são uma classe de peptídeos antimicrobianos (AMPs - do inglês Antimicrobial peptide) cíclicos de plantas, compostos de, aproximadamente, 30 resíduos de aminoácidos, sendo seis cisteínas conservadas e conectadas por três pontes de dissulfeto. Sua expressão é constitutiva, tendo sua principal função na defesa vegetal contra patógenos, que podem causar perdas significativas em culturas importantes para a agricultura, como no caso da família Poaceae que apresenta destacada importância econômica no Brasil e no mundo. Nesse estudo foi conduzida uma busca por genes relacionados a ciclotídeos vegetais, disponíveis em bancos de dados de acesso restrito e público, com vistas ao isolamento e caracterização in silico desses peptídeos. Através da busca nos genomas de Hevea brasiliensis, Manihot esculenta, Ricinus communis, Sorghum bicolor e Zea mays; bem como no transcriptoma de Vigna unguiculata foi verificado que apenas o genoma de Zea mays apresentou dois possíveis genes codificadores de ciclotídeos. Assim, primers foram desenhados para o isolamento destes genes em milho. Além da espécie Z. mays, as espécies Triticum aestivum (trigo) e Secale cereale (centeio), foram utilizadas para a tentativa de isolamento a partir dos pares de primers desenhados. Foram obtidos 19 fragmentos (amplicons), sendo quatro deles (zm315, zm316, zm317, sc359) com o domínio ciclotídeo, os três primeiros de milho e o último de centeio. Essas quatro sequências foram, então, submetidas a uma caracterização in silico, para predição da estrutura secundaria, terciaria e função predita. Verificou-se que esses peptídeos apresentam as seis cisteínas conservadas, três pontes dissulfeto e o padrão de aminoácidos entre as cisteínas, similar aos encontrados em ciclotídeos. Ainda foi possível a predição de algumas propriedades físico-químicas e modelagem por homologia para as quatro proteínas, o que mostrou a qualidade e confiabilidade dos modelos. Sugere-se que dois dos ciclotídeos isolados (zm315, zm316) pertençam a uma nova classe de peptídeos lineares, mas com características de ciclotídeos. / Cyclotides are a class of cyclic antimicrobial peptides (AMPs) present on plants, composed by approximately 30 amino acid residues, including six conserved cysteines connected by three disulphide bridges. Its expression is constitutive, with main function on plant defense against pathogens, that may cause significant losses in important cultivars, as in the case of Poaceae, a family that presents economic importance for the agriculture in Brazil and worldwide. This study performed a search for genes related to plant cyclotides, available in restricted and public access databases, aimed at their in silico isolation and characterization. Searching for these peptides in Hevea brasiliensis, Manihot esculenta, Ricinus communis, Sorghum bicolor, Vigna unguiculata and Zea mays genomes, we obtained two possible genes encoding Cyclotides in Z. mays. Thus, primers were designed for the isolation of these genes in maize as well in wheat (Triticum aestivum) and rye (Secale cereale) species. We obtained 19 amplicons and four of them (zm315, zm316, zm317, sc359) presented cyclotide domain. These four sequences were then subjected to in silico characterization, for predicting their secondary and tertiary structures, as well their function. It was found that these peptides present six conserved cysteines, three disulphide bridges and the amino acid pattern between the cysteines similar to those found in cyclotides. It was also possible to predict some physical chemical properties and also building a 3D protein by homology modeling for the four peptides, presenting high quality and reliability. Our analysis indicates that two isolated cyclotides (zm315, zm316) appear to belong to a new class of linear peptides, but with cyclotide features.

Made available in DSpace on 2017-07-10T17:37:24Z (GMT). No. of bitstreams: 1 Marcos_Cesar_Mottin.pdf: 1463774 bytes, checksum: 7b3088494ffb35b40e094d13189330bb (MD5) Previous issue date: 2016-02-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The agricultural production systems have as a fundamental component soil. inadequate cultural practices associated with monoculture has caused soil degradation, natural resources and the productivity of planted crops. This study aimed to evaluate the productivity of biomass cover crops in autumn-winter (Poaceae and Fabaceae), and its effects on soil physical properties at different depths and; Evaluate the productivity of corn and soybean in succession to cover crops (Poaceae and Fabaceae) grown in autumn-winter. The experimental design was randomized blocks with split plots with six replications. The plots consisted of four cover crops in autumn-winter; two Poaceae (black oats and pasture) and two Fabaceae (pea forage and white lupine), and the trade of summer crops (corn and soybeans) grown in succession on these different biomasses. The subplots were different depths reviews (0 - 0.05, 0.05 to 0.10 and 0.10 to 0.15 m). The factors evaluated in this study were: dry matter productivity; soil surface coverage ratio; macroporosity, microporosity, total porosity; bulk density; soil penetration resistance and parameters of production and productivity of commercial summer crops corn and soybean. The plants of the family Poaceae had lower dry mass productivity, however, had higher soil surface coverage ratio and macroporosity. The cover crops cultivation in autumn-winter, promoted to the soil in depth from 0 to 0.05 m, higher macroporosity and total porosity, and lower density. The resistance to penetration depth 0.05 to 0.20 m was smaller in area cultivated with plants Poaceae family. Growing Family Poaceae cover crops (black oats and pasture) and Fabaceae (pea forage and white lupine) in autumn-winter, did not influence the productivity of corn and soybean grown in succession / Os sistemas de produção agrícola têm como componente fundamental o solo. Práticas culturais inadequadas associadas ao monocultivo têm causado degradação do solo, dos recursos naturais e da produtividade das culturas implantadas. O presente trabalho teve como objetivos: Avaliar a produtividade de biomassa de plantas de cobertura no outono-inverno (Poaceae e Fabaceae), e seus efeitos nas propriedades físicas do solo em diferentes profundidades e; Avaliar a produtividade de grãos de milho e soja em sucessão a plantas de cobertura (Poaceae e Fabaceae) cultivadas no outono-inverno. O delineamento experimental utilizado foi de blocos ao acaso com parcelas subdivididas, com seis repetições. As parcelas foram constituídas de quatro plantas de cobertura no outono-inverno; duas Poaceae (aveia preta e braquiária) e duas Fabaceae (ervilha forrageira e tremoço branco), sendo as culturas comerciais de verão (milho e soja) cultivadas em sucessão sobre essas diferentes biomassas. As subparcelas foram as diferentes profundidades de avaliações (0 - 0,05; 0,05 - 0,10 e 0,10 - 0,15 m). Os fatores avaliados nesse trabalho foram: Produtividade de massa seca; índice de cobertura da superfície do solo; volume de macroporos, microporos, porosidade total; densidade do solo; resistência do solo à penetração e os parâmetros de produção e produtividade das culturas comerciais de verão, milho e soja. As plantas da família Poaceae apresentaram menor produtividade de massa seca, no entanto, obtiveram maior índice de cobertura da superfície do solo e volume de macroporos. O cultivo de plantas de cobertura no outono-inverno, promoveu ao solo na profundidade de 0 - 0,05 m, maior volume de macroporos e porosidade total, e menor densidade. A resistência do solo à penetração na profundidade de 0,05 - 0,20 m foi menor na área cultivada com plantas da família Poaceae. O cultivo de plantas de cobertura da família Poaceae (Aveia preta e braquiária) e Fabaceae (Ervilha forrageira e Tremoço branco) no outono-inverno, não influenciaram na produtividade de grãos de milho e soja cultivados em sucessão

Ce mémoire présente l'étude du signal phytolithique de sédiments mio-pliocènes du Tchad(Afrique Centrale) datés entre 7-2 Ma, et contemporains des Homininés anciens Sahelanthropustchadensis et Australopithecus bahrelghazali. Une calibration de la relation plantes-phytolithes-solspour l'Afrique tropicale subsaharienne actuelle a d'abord été réalisée pour apprécier la signatureenvironnementale des phytolithes dans le registre fossile. L'analyse des assemblages phytolithiques de98 espèces de graminées (Poaceae) a permis d'élaborer trois nouveaux indices phytolithiques à partirde 43 types propres aux Poaceae. Testés sur une base de 57 sols/sédiments modernes du Tchad, cesindices permettent de tracer les associations graminéennes aquatiques du Lac Tchad, les associationsmésophytiques des milieux humides soudaniens, et les associations xérophytiques des milieux secssahéliens. L'analyse des assemblages phytolithiques des sols/sédiments actuels considérés dans leurensemble a permis d'évaluer le potentiel de ce proxy à caractériser la physionomie des formationssoudano-sahéliennes modernes. La calibration a été appliquée à l'étude d'un enregistrementsédimentaire discontinu du Lac Tchad (6-2 Ma) (forage de Bol, 13°N/14°E) et à celle de 18 niveauxpaléontologiques du Djourab (7-3.5 Ma) (16°N/17°E). Les résultats indiquent la présence de savanesintermédiaires à fermées et de zones de végétation aquatique dominantes à 7 Ma dans le Djourab, puisde savanes plus ouvertes et sèches à 3.5 Ma. Une phase de bas niveau lacustre est enregistrée entre3.6-2.8 Ma à Bol, et un pic d'aridité à 3.2 Ma. Enfin, les résultats montrent l'existence de graminéesen C4 au Tchad depuis 7 Ma. / This thesis dissertation is dedicated to the study of the phytolith signal of Mio-Pliocenesediments from Chad (Central Africa) dated between 7-2 Ma, and contemporary to the early Homininspecies Sahelanthropus tchadensis and Australopithecus bahrelghazali. A calibration work studyingthe relationship plants-phytoliths-soils in modern sub-Saharan tropical Africa was carried out in orderto assess the environmental significance of the phytolith signal in the fossil record. Phytolithassemblages produced by 98 sub-Saharan grass species (Poaceae) were analyzed and the results led tothe development of three new phytolith indices defined from 43 types specific to Poaceae. Tested on adatabase of 57 modern soil/sediment samples from Chad, these indices allow drawing aquatic grassassociations of Lake Chad, mesophytic grass associations of wetlands from the Sudanian domain, andxerophytic grass associations of drylands from the Sahelian domain. The analysis of modern soilphytolith assemblages (total assemblages) was used to assess the potential of this proxy to characterizethe physiognomy of the Sudano-Sahelian vegetation types. The calibration had been applied to thestudy of a discontinuous sedimentary record from Lake Chad (6-2 Ma) (Bol core, 13°N/14°E) and of18 paleontological levels from the Djourab (7-3.5 Ma) (16°N/17°E). The results indicate thedominance of intermediate to closed savannas and areas of aquatic vegetation at 7 Ma in the Djourab,and more open and dry savannas at 3.5 Ma. A limited lacustrine stage is recorded between 3.6-2.8 Maat Bol, and a shift of aridity at 3.2 Ma. Finally, the results show the existence of C4 grasses in Chadsince 7 Ma.

Submitted by Michele Mologni (mologni@unoeste.br) on 2018-05-11T18:59:04Z No. of bitstreams: 1 Rafaelle Persoli de Aguiar.pdf: 767469 bytes, checksum: 2a89b36310d152e23981c917f03806f7 (MD5) / Made available in DSpace on 2018-05-11T18:59:04Z (GMT). No. of bitstreams: 1 Rafaelle Persoli de Aguiar.pdf: 767469 bytes, checksum: 2a89b36310d152e23981c917f03806f7 (MD5) Previous issue date: 2017-12-07 / The speed and amplitude of tropical pasture expansion in Brazil are associated with the availability of high quality seeds, thus the country is considered the largest producer, consumer and exporter of tropical forage grass seed in the world. The objective of this work was the establishment of vigor classes for seeds of Urochloa brizantha cv Marandu via digitized images made from the tetrazolium test. The project was carried out from March to December 2016 at the University of Oeste Paulista (UNOESTE) Seed Laboratory in Presidente Prudente, SP. The analyzes were carried out in two experiments using six seed lots of Urochloa brizantha cv Marandu, in order to classify the seeds into three distinct classes: viable and vigorous, viable and non - vigorous and non - viable. In the second step besides the differential use of two parts of the seed for the tetrazolium test two concentrations were used 0.1% and 1% of salt 2, 3, 5 triphenyl tetrazolium chloride. The tests carried out were: germination test, tetrazolium test, emergency test, IVE (emergence speed index), shoot length and root and dry matter mass of shoot and root. All the tests performed followed the rules for the Rules for Seed Analysis. The use of scanned images through the two methods (scanner and camera) proved to be efficient for determination of the viability of the seeds of Urochloa brizantha cv Marandu, but the results of seed vigor classification using scanned images using vigor tests did not were promising. / A velocidade e a amplitude da expansão de pastagens tropicais, no Brasil, estão associadas à disponibilidade de sementes de alta qualidade, dessa maneira o país é considerado o maior produtor, consumidor e exportador de sementes de gramíneas forrageiras tropicais do mundo. O objetivo desse trabalho foi o estabelecimento de classes de vigor para sementes de Urochloa brizantha cv Marandu via imagens digitalizadas realizadas a partir do teste de tetrazólio. O projeto foi realizado no período de março a dezembro de 2016, no Laboratório de Sementes da Universidade do Oeste Paulista (UNOESTE), em Presidente Prudente, SP. As análises foram realizadas em dois experimentos, utilizando seis lotes de sementes de Urochloa brizantha cv Marandu, com o intuito de classificar as sementes em três classes distintas, sendo elas: viáveis e vigorosas, viáveis e não vigorosas e não viáveis. Na segunda etapa além do diferencial de utilização de duas partes da semente para o teste de tetrazólio foram utilizadas duas concentrações 0,1% e 1% de sal 2, 3, 5 trifenil cloreto de tetrazólio. Os testes realizados foram: teste de germinação, teste de tetrazólio, teste de emergência, IVE (índice de velocidade de emergência), comprimento de parte aérea e raiz e massa de matéria seca de parte aérea e raiz. Todos os testes realizados seguiram as normas referentes às Regras para Análise de Sementes. A utilização de imagens digitalizadas através dos dois métodos (escâner e câmera) se mostrou eficiente para determinação de viabilidade das sementes de Urochloa brizantha cv Marandu, porém os resultados de classificação de vigor de sementes, através de imagens digitalizadas, utilizando testes de vigor, não foram promissores.