Made available in DSpace on 2016-06-02T18:55:21Z (GMT). No. of bitstreams: 1 4057.pdf: 2122562 bytes, checksum: c5fde2aa056e5c4a8b5e9d536009b775 (MD5) Previous issue date: 2012-01-16 / Financiadora de Estudos e Projetos / The genus Conyza includes approximately 60 species, which are distributed throughout most of the world. Globally the weed species Conyza canadensis and Conyza bonariensis infest more than 40 types of crops. Both species are noted for their ability to infest abandoned areas (vacant lots and roadsides), pastures, perennial crops (citrus and coffee) and annual crops (cotton, corn, soybeans and wheat). Knowledge of the biology of these weeds is required to inform management actions to control their spread for example to identify which is the best control strategy and time for action. We conducted experiments at the Center for Agricultural Sciences / UFSCar, between 2010 and 2011, to achieve 3 research objectives: (1) determine the germination behavior of C. canadensis and C. bonariensis under different environmental conditions [different temperatures (10oC, 15oC, 20oC, 25oC, 30oC and 35oC), light (with and without), sowing depth (0, 0.5, 1, 2, 3, 5, 7, and 10 cm) and germination in soils with different textures (sand, intermediate and clay)], (2) characterize the different types of leaf surface of C. bonariensis and C. canadensis by scanning electron microscopy, (3) determine the effects of the application of the herbicide glyphosate (0.42 kg a.i. ha-1), when mixed with ammonium glyphosate (0.5 kg a.i. ha-1), bentazon (0.72 kg a.i. ha-1), chlorimuron-ethyl (0.15 kg a.i. ha-1), carfentrazone-ethyl (0.03 kg a.i. ha-1), 2,4-D (1.0 L a.i. ha-1), metribuzin (0.48 kg a.i. ha-1) and sulfentrazone (0.6 kg ha-1), in addition to these herbicides applied in isolation. For both C. bonariensis and C. canadensis, the best seed germination and germination rate temperature was approximately 250C. Seed germination rate of both species was higher when exposed to light, compared with seeds germinated in the dark. Sowing depth and soil texture also influenced germination, with seeds of both species showing higher emergence rates in intermediate texture soils when they were sown on the soil surface (0 cm), whereas emergence rates declined at sowing depths ≥0.5 cm. Analysis of leaf surfaces revealed that both species are amphistomatic with stomata on the adaxial and abaxial leaf surfaces, that the non-glandular trichomes are unicellular and multicellular, and that C. bonariensis has a visually larger amount of trichomes on the adaxial surface. The most effective herbicide treatments for the chemical control of C. bonariensis were glyphosate + ammonium glyphosate, glyphosate + bentazon, glyphosate + chlorimuron - ethyl and glyphosate + metribuzin, whereas for C. canadensis, the best treatments were mixtures of glyphosate + ammonium glyphosate, glyphosate + bentazon and glyphosate + metribuzin. / O gênero Conyza inclui aproximadamente 60 espécies, as quais se distribuem em quase todo o mundo. As espécies Conyza canadensis e Conyza bonariensis, destacam-se por infestarem áreas abandonadas (terrenos baldios e margens de estradas), pastagens, culturas perenes (citros e café) e lavouras anuais (algodão, milho, soja e trigo). Em termos mundiais, estas espécies daninhas infestam mais de 40 culturas. É importante, quando se pensa em manejo das plantas daninhas, conhecer a biologia das plantas alvos, para assim detectar qual é o melhor controle e momento de ação. O experimento foi realizado no Centro de Ciências Agrárias/UFSCar, entre os anos de 2010 e 2011. Os objetivos desta pesquisa foram: (1) determinar o comportamento germinativo de C. canadensis e C. bonariensis em diferentes condições de temperatura (10oC, 15oC, 20oC, 25oC, 30oC e 35oC), luz (presença e ausência), profundidade de semeadura (0, 0.5, 1, 2, 3, 5, 7, e 10 cm) e germinação em solos com diferentes texturas (arenosa, média e argilosa); (2) caracterizar a superfície foliar das diferentes espécies de C. bonariensis e C. canadensis através da microscopia eletrônica de varredura; (3) determinar o tipo de interação do herbicida glyphosate (0,42 kg i.a ha-1), quando em mistura com amônio glufosinato (0,5 kg i.a ha-1), bentazon (0,72 kg i.a ha-1), chlorimuron - ethyl (0,15 kg i.a ha-1), carfentrazone - ethyl (0,03 kg i.a ha-1), 2,4-D (1,0 L i.a ha-1 ), metribuzin (0,48 kg i.a ha-1) e sulfentrazone (0,6 kg i.a ha-1), além dos mesmos herbicidas aplicados isoladamente. Para C. bonariensis e C. canadensis, a melhor temperatura para a germinação das sementes e índice de velocidade de germinação foi de aproximadamente 250C; ambas as espécies obtiveram maior taxa de germinação quando submetidas à luz comparadas com o tratamento de escuro absoluto, em relação à profundidade de semeadura nos diferentes solos, as sementes de ambas as espécies obtiveram maior taxa de emergência em solo de textura média quando estavam na superfície do solo (0 cm) a partir de 0,5 cm ocorreu redução da emergência das plântulas. Ambas as espécies são anfiestomáticas, apresentam estômatos na superfície adaxial e abaxial, possuem tricomas tectores unicelulares e pluricelulares, sendo que a espécie C. bonariensis possui visualmente maior quantidade de tricomas na face adaxial. Em relação ao manejo químico os tratamentos utilizando glyphosate + amônio - glufosinato, glyphosate + bentazon, glyphosate + chlorimuron - ethyl e glyphosate + metribuzin foram mais efetivos no controle de C. bonariensis; para C. canadensis, os melhores tratamentos foram às misturas de glyphosate + amônio - glufosinato, glyphosate + bentazon e glyphosate + metribuzin.

A ocorrência de potenciais de ação e neurotransmissores, componentes principais do sistema nervoso animal, em plantas, bactérias e fungos mostra a universalidade dos princípios de sinalização e transmissão de informações na forma de sinais químicos e elétricos em todos os organismos. Esses tópicos de estudo, juntamente com inteligência em plantas e transporte vesicular de auxina, constituem as linhas de pesquisa principais da recém-criada Neurobiologia Vegetal. Entre os neurotransmissores encontrados em plantas, a acetilcolina atua, entre outras situações, no crescimento e desenvolvimento controlado pelo fitocromo e na permeabilidade iônica de membranas. Nesse contexto, foi sugerido que a acetilcolina pode desempenhar um papel importante na regulação do movimento estomático, tendo efeito estimulatório na abertura dos estômatos além de poder atuar na sinalização entre raiz e parte aérea. Dessa forma, foi proposto identificar a presença deste neurotransmissor em plantas de milho hidratadas e submetidas a estresse hídrico, com o objetivo de correlacionar a presença de acetilcolina com as respostas estomáticas de tais plantas. Além disso, foi objetivo do trabalho avaliar parâmetros fisiológicos como potencial hídrico, condutância estomática, transpiração e fotossíntese líquida e suas possíveis relações com a acetilcolina em três folhas das plantas hidratadas e estressadas. Para tanto, foi montado um experimento em blocos casualizados em esquema fatorial (2x3). Os fatores foram: água, nos níveis de hidratação e estresse, e idade das folhas nos níveis folha 4 (mais velha), folha 5 (idade intermediária) e folha 7 (mais jovem). As plantas foram divididas em 20 blocos, contendo uma planta hidratada e uma sob estresse cada e as análises fisiológicas feitas nas três folhas. As plantas foram colocadas em câmara de crescimento tipo BOD com controle de iluminação e temperatura. Após análises fisiológicas, as folhas foram utilizadas para extração e determinação de acetilcolina. Os extratos purificados e secos foram submetidos à pirólise e cromatografia gasosa e as substâncias identificadas por espectrometria de massas. Não foi detectada acetilcolina nas plantas, apesar de estudos anteriores demonstrarem sua ocorrência em folhas e sementes de milho. Hipóteses foram levantadas para explicar tal fato. Quanto as variáveis fisiológicas, o déficit hídrico reduziu em aproximadamente 59% a transpiração, em 65% a condutância estomática e em 59% a fotossíntese das plantas. Condutância estomática e transpiração, condutância e fotossíntese, e transpiração e fotossíntese apresentaram intensa correlação. Já o potencial hídrico teve baixa correlação com essas variáveis. Quanto ao fator idade, folhas 7 apresentaram maiores valores de fotossíntese, condutância e transpiração que as folhas 4 e 5. / The occurrence of action potential and neurotransmitters, the major components of animal nervous system, in plants, bacteria and fungi, shows the universality of signaling principles and information transmission in the way of chemical and electrical signals in all organisms. These study topics, along with plant intelligence and vesicular-based auxin transport, constitute the major research lines of the newly created Plant Neurobiology. Among the neurotransmitters found in plants, the acetylcholine plays a role in phytochromecontrolled growth and development and in membrane ion permeability. In this context, it was suggested that acetylcholine can play an important role in the regulation of stomatal movements, having stimulatory effect in the stomatal opening. In addition it can play a role in root-to-shoot signaling process. Therefore, it was proposed to identify the presence of this neurotransmitter in maize plants hydrated and under water stress, with the aim of correlating the presence of acetylcholine with the stomatal responses of such plants. Moreover, another aim of the study was to evaluate physiological parameters like water potential, stomatal conductance, transpiration rate and net photosynthetic rate and their possible relationship with the acetylcholine in three leaves of hydrated and stressed plants. Therefore, an experiment was set up in randomized block design in 2x3 factorial. The factors were: water, in the levels of hydration and stress, and leaves age in the levels leaf 4 (older), leaf 5 (intermediary age) and leaf 7 (younger). The plants were divided in 20 blocks, and each one has had one hydrated plant and one stressed plant and the physiological analysis was made in three leaves. The plants were placed in B.O.D. growth chamber under controlled conditions of light and temperature. After the physiological analysis, the leaves were used to extraction and determination of acetylcholine. The dried and purified extracts were subjected to pyrolysis and gas chromatography and the substances identified by mass spectrometry. The acetylcholine was not detected in plants, although earlier studies have had demonstrated its occurrence in maize leaves and seeds. Hypotheses were elaborated to explain such fact. Regarding the physiological variables, water stress reduced the plants transpiration rate in 59%, stomatal conductance in 65% and net photosynthesis in 59%. Stomatal conductance, transpiration and photosynthesis were strongly related. On the other hand, the water potential showed weak correlation with that variable. As for the age factor, leaves 7 had higher photosynthetic rates, conductance and transpiration than the leaves 4 and 5.

Made available in DSpace on 2014-08-20T13:59:11Z (GMT). No. of bitstreams: 1 dissertacao_janete_mariza_adamski.pdf: 870957 bytes, checksum: 3780a4713aace89a20cbc46f8e882d7f (MD5) Previous issue date: 2011-02-15 / Iron is an essential element for growth and development of plants and is involved in essential metabolic processes such as photosynthesis and respiration. However, homeostasis of this metal is essential, both excess and deficiency are harmful. One of the characteristic symptoms of deficiency is chlorosis, caused by the decrease in chlorophyll biosynthesis. On the other hand, the free iron in excess can cause oxidative stress. Study of the effects of different concentrations of iron in morphological, physiological or biochemical parameters are essential to a better understanding of this nutrient homeostasis in plants. In the present work, plants of sweet potato were submitted under hydroponics system, to different concentrations of ferric-EDTA in nutrient solution: 0.45; 0.9; 4.5 and 9.0 mmol dm-3. Photosynthetic and growth characteristics, nutrient absorption, antioxidant enzymes, stomatal density and diameter, ultra structure of root and leaves cells and histochemical iron in the leaves were evaluated. The toxicity of iron in excess (9.0 mmol dm-3) led to the appearance of brown spots on leaves, often forming necroses, with significant reductions in growth. In these plants, the activity of superoxide dismutase and ascorbate peroxidase increased. Also, the absorption of other micronutrients was affected mainly of the manganese. The iron content in the shoot increased, also qualitatively confirmed by the histochemical test. The light reactions of photosynthesis were not affected, but there was a decrease in stomatal density and net assimilation rate. The ultra structure of root cells reveals the damage of mitochondria in treatments with high concentrations of iron. However, in these plants, the ultra structure of chloroplasts is not affected. / O ferro é um elemento essencial para o crescimento e desenvolvimento das plantas, estando envolvido em processos metabólicos essenciais, como fotossíntese e respiração. Entretanto, a homeostase desse metal é fundamental, pois tanto o excesso quanto a deficiência são prejudiciais. Um dos sintomas característico da deficiência é a clorose, causada pelo decréscimo na biossíntese da clorofila. Por outro lado, o ferro quando livre e em excesso pode gerar estresse oxidativo. Buscar entender os efeitos de diferentes concentrações de ferro, em nível morfológico, fisiológico ou bioquímico, é indispensável para um melhor entendimento da homeostase desse micronutriente nas plantas. No presente trabalho, plantas de batata-doce foram submetidas, sob sistema de hidroponia, a diferentes concentrações de EDTA-férrico em solução nutritiva: 0,45; 0,9; 4,5 e 9,0 mmol dm-3. Foram avaliadas características fotossintéticas e de crescimento, absorção de nutrientes, atividade de enzimas antioxidantes, densidade e tamanhos dos estômatos, ultra-estrutura de células radiciais e de células da folha e histoquímica do ferro nos tecidos foliares. A toxidez por excesso de ferro (9,0 mmol dm-3) levou ao surgimento de manchas marrons nas folhas, muitas vezes formando necroses, com reduções significativas no crescimento. Nestas plantas, a atividade da superóxido dismutase e ascorbato peroxidase aumentou. Também, a absorção dos demais micronutrientes foi afetada, principalmente do Mn. O teor de ferro na parte aérea aumentou significativamente, sendo visualizado pelo teste histoquímico. As reações luminosas da fotossíntese não foram comprometidas, porém houve queda na densidade estomática e na taxa assimilatória líquida. A ultra-estrutura das células radiciais revela o comprometimento das mitocôndrias nos tratamentos com altas concentrações de ferro. Porém, nestas plantas, a ultra-estrutura dos cloroplastos não é afetada.

Sur l’épiderme des feuilles des végétaux supérieurs, se trouvent des pores appelés stomates et composés de deux cellules spécialisées, les cellules de garde. La régulation des mouvements stomatiques en réponse aux signaux de l’environnement permet le contrôle des échanges gazeux de la plante avec l’atmosphère. Ces mouvements sont dus à des variations rapides de la turgescence des cellules de garde. Les H+-ATPases sont des pompes à protons situées sur la membrane plasmique des cellules des végétaux. En excrétant les ions H+ dans l’apoplasme, ces protéines génèrent une force protomotrice capable de fournir l’énergie nécessaire à l’activation de canaux et transporteurs ioniques membranaires. Ce processus permet de contrôler la turgescence des cellules de garde. Des analyses d’expression nous ont permis d’identifier les trois isoformes d’H+-ATPases, AHA1, AHA2 et AHA5, exprimées dans la cellule de garde. Des études in silico nous ont révélé qu’en dépit d’une forte proximité génétique, ces trois protéines semblent être impliquées dans des voies de signalisation différentes. La caractérisation phénotypique d’une collection de mutants affectés dans l’expression de chacune des isoformes nous a permis de mettre en évidence qu’AHA1 est l’H+-ATPase spécifique de la réponse stomatique à la lumière bleue et que la perte d’expression de cette isoforme confère à la plante une croissance plus faible et une meilleure tolérance à la sécheresse que le sauvage. Enfin, nous avons confirmé par des études d’électrophysiologie et par l’élaboration de sondes fluorescentes pH-sensibles l’implication directe d’AHA1 dans la voie de signalisation de la lumière bleue dans la cellule de garde. / Stomata are pores laocated on high plant leaf epidermis and formed by two specialized guard cells. Stomatal movement regulation in response to environment allows the control plant-atmosphere gas exchanges. Stomatal movements are ruled by rapid turgor changes in guard cells. H+-ATPases are proton pomps expressed on plant cell plasma membrane. By extruding H+ in the apoplast, these proteins generate a protomotive force able to activate secondary ionic transporters and channels. This process leads to changes in ion homeostasy and in fine to turgor changes in the guard cell. Expression analyses allowed us to identify the three AHAs isoforms expressed in the guard cell : AHA1, AHA2 and AHA5. In silico study indicates that despite the high identity percentage between the three proteins, they seem involved in differents signalisation pathways. Phenotypic characterization of mutants impaired in the expression of each AHAs allowed us to conclude that AHA1 is specific for the blue light stomatal response. Furthermore, the lack of AHA1 leads to a lower growth and a better tolerance to drought stress of aha1 mutant compare to the wild type. Sugar metabolism studies in aha1 mutant gave us informations on the compensatory mecanism for stomatal opening in this mutant. Finally, we confirmed by electrophisiologcal studies and by fluorescent pH sensitive probes elaboration, the specific involvement of AHA1 in blue light signalisation pathway in the guard cell.

De nombreux processus physiologiques tels que les mouvements stomatiques, l’absorption des nutriments, l’élongation cellulaire et la signalisation cellulaire impliquent des flux d’anions entre les membranes plasmique et vacuolaire des cellules végétales. Ces flux ioniques sont régulés par des canaux et transporteurs membranaires. Les canaux ioniques transportent passivement les ions au travers des membranes selon le gradient électrochimique. Les transporteurs actifs permettent le transport contre le gradient électrochimique de l’ion transporté induisant son accumulation dans un compartiment cellulaire. Dans les cellules végétales, le gradient de H+ entre différents compartiments constitue la principale source d’énergie couplée par les symports et les antiports au transport de NO₃⁻ et Cl⁻. Au cours de ma thèse, j’ai analysé ces flux ioniques avec deux approches. Une première approche a consisté en l’étude fonctionnelle par électrophysiologie de deux protéines membranaires, AtCLCc et AtCLCg impliquées dans le transport d’anions. Dans une deuxième approche, un biosenseur, clopHensor a été exprimé chez A. thaliana et a permis de mesurer simultanément la [NO₃⁻] et le pH cytosoliques in vivo. Les cellules de garde ont été choisies comme modèle cellulaire pour l’étude de la dynamique in vivo de la [NO₃⁻]cyt et du pH. Nous avons mis en évidence que la [NO₃⁻]cyt est influencée par les conditions extracellulaires dans ces cellules. Enfin l’expression de clopHensor en plantes KO pour un antiport NO₃⁻/H⁺ vacuolaire, AtCLCa, et d’un canal anionique de la membrane plasmique, SLAC1, nous a permis d’étudier la contribution de deux membranes dans la régulation de [NO₃⁻] et du pH cytosolique. Les travaux menés ont permis de visualiser l’activité de canaux et de transporteurs d’anions et H⁺ in vivo et de quantifier leur impact sur l’homéostasie du cytosol. / Many physiological processes like stomata aperture, nutrient up-take, cellular elongation and cell signalling involve anion fluxes at the two main membranes, the plasma and vacuolar membranes of plant cells. Specialized membrane proteins form active and passive anion transport systems mediating and regulating anion fluxes. Ion channels are passive transport systems mediating ion fluxes across membranes along the electrochemical gradient. Whereas active transporters work against the electrochemical gradient of the transported ion allowing its accumulation into a cellular compartment. In plant cells, the H⁺ gradient is the main energy source of antiporters and symporters that couple the transport of anions like NO₃⁻ and Cl⁻ to the transport of H⁺. In the presents work, we aimed at analysing anion and H⁺ fluxes at two levels. First, we used an electrophysiological approach to study the functional properties of two anion transport systems acting at the vacuolar membrane, AtCLCc and AtCLCg. We also expressed a biosensor, clopHensor in A. thaliana to dynamically measure in vivo the [NO₃⁻] and pH of the cytosol. We chose stomata guard cells as a cellular model to study these fluxes. Our results illustrate the in vivo dynamics of cytosolic [NO₃⁻] and pH variations in the cytosol of guard cells. Our data show that in guard cells the cytosolic [NO₃⁻] is highly influenced by the extracellular [NO₃⁻]. At last, clopHensor’s expression in plants KO for the vacuolar NO₃⁻/H⁺ antiporter AtCLCa and for the plasma membrane anion channel SLAC1 allowed us to dissect the role of the two membranes in controlling the variation of cytosolic [NO₃⁻] and pH. This work enabled to visualize the activity of an anion channel (SLAC1) and of a NO₃⁻/H⁺ antiporter (AtCLCa) in vivo and to quantify the impact of anion and proton fluxes on cytosolic homeostasis of guard cells.

No description available.

Le mildiou est une maladie de la vigne affectant les feuilles et les baies et pouvant entraîner des diminutions importantes de la quantité et de la qualité de la vendange. L'agent responsable, Plasmopara viticola, un oomycète biotrophe obligatoire, provoque différentes altérations physiologiques au niveau de la feuille infectée. D'une part, il y a des accumulations anormales d'amidon au niveau des taches d'huile, symptômes caractéristiques de la maladie. D'autre part, l'infection induit une dérégulation des mouvements stomatiques. Les stomates, ouvertures naturelles permettant les échanges gazeux entre la plante et l'atmosphère, restent anormalement ouverts de nuit et ne se ferment plus en réponse à un stress hydrique ou à un traitement à l'ABA. Les deux parties de cette thèse avaient pour objectif de i) expliquer l'origine et le mécanisme de l'accumulation d'amidon et ii) isoler et identifier le facteur responsable de la dérégulation stomatique. Les modifications du métabolisme de l'amidon au niveau des feuilles infectées ont d'abord été étudiées à l'aide d'une analyse transcriptomique afin d'identifier les gènes codant pour des enzymes impliquées dans ce métabolisme dont l'expression était affectée. Après validation de deux gènes de référence, une étude par qRT-PCR a permis de vérifier les changements d'expression de certains de ces gènes au cours de la cinétique de l'infection, puis les activités des enzymes correspondantes ont été déterminées. Ces approches, complétées par des dosages de l'amidon et des sucres solubles ainsi que la mesure de l'activité photosynthétique, ont permis de corréler différents événements avec l'infection. D'après nos résultats, l'accumulation de l'amidon dans les taches d'huile pourrait résulter d'une augmentation de sa synthèse liée à l'augmentation de l'activité AGPase, combinée à une diminution de sa dégradation par modification de l'activité des amylases. Une diminution de la photosynthèse et une augmentation de l'activité invertase traduisent une transition source-puits au niveau des taches d'huile. La deuxième partie de la thèse a porté sur la recherche d'une molécule soluble d'origine végétale ou pathogène, secrétée dans l'apoplasme au cours de l'infection et responsable du dysfonctionnement stomatique. Sur « épidermes isolés », les fluides apoplastiques extraits de feuilles infectées induisent une ouverture stomatique à l'obscurité et contrecarrent la fermeture induite par l'ABA à la lumière, mimant ainsi la dérégulation observée sur feuille entière. Le composé actif serait une protéine assez stable, de taille >50 kDa et modifiée post-traductionellement par une glycosylation essentielle à son activité sur l'ouverture stomatique. Après séparation par chromatographie d'exclusion des fluides apoplastiques de feuilles infectées, deux fractions ont été retenues : une présentant une forte activité sur l'ouverture stomatique, et une seconde sans activité. Neuf protéines de vigne ont été identi fiées spécifiquement dans la fraction active après une analyse comparative de ces deux échantillons par spectrométrie de masse. Des expérimentations supplémentaires seront nécessaires pour purifier et identifier la protéine recherchée. / The grapevine downy mildew affects leaves and young berries and can affect the harvest quality and quantity. The causal agent is the obligate biotroph oomycete Plasmopara viticola that induces severe physiological alterations in infected leaves. One is the abnormal accumulation of starch in oil spots, the characteristic symptoms of the disease. Another is a deregulation of stomatal movements. Stomata, natural openings on the leaf surface allowing gas exchanges between the plant and the atmosphere, stay abnormally open during the night and do no longer close upon water stress or ABA treatment in infected leaves. This thesis is divided into two chapters that aim to i) explain the origin and mechanism of the abnormal starch accumulation and ii) isolate and identify the compound responsible for the stomatal deregulation. The modifications of starch metabolism in infected leaves were first studied by transcriptomic analysis allowing to identify transcriptional modifications of genes involved in starch metabolism. After the validation of two reference genes, a qRT-PCR analysis was performed in order to verify the expression alterations of some of these genes and the corresponding enzymatic activities were measured. The quantification of soluble sugars and starch, and the measurement of photosynthetic activity were included in the analysis and their alterations could be correlated with the infection. Altogether, the obtained results hint towards an increase of starch synthesis via an increase in AGPase activity, that, combined with a decrease of its degradation by modification of amylase activities, could be responsible for the observed starch accumulation in oil spots. Concurrently, a source-sink transition is apparent in infected leaves by decrease of photosynthetic activity and increase of a cell wall invertase activity. The second part of this thesis dealt with a soluble molecule of plant or pathogen origin that is secreted into the apoplast during infection and could be responsible for the stomatal deregulation. The apoplastic wash fluids from infected leaves increase tha stomatal aperture in the dark in grapevine epidermal peels and counteract the ABA-induced stomatal closure, thus mimicking the deregulation observed on whole leaves. The active compound seems to be a stable protein of > 50kDa with a glycosylation that is essentiel for its activity. After separation of the fluids by size exclusion chromatography, two fractions were compared : one active on stomatal aperture and an inactive one. 9 grapevine proteins could be identified in the active sample by mass spectrometry analysis, but further analyses are needed to purify and identify the one responsible for the stomatal deregulation.

Submitted by Maria Beatriz Vieira (mbeatriz.vieira@gmail.com) on 2017-06-14T12:26:32Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) tese_carlos_davi_santos_e_silva.pdf: 1996582 bytes, checksum: f5e5507222353ab43be89856ea18958b (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-06-14T20:55:21Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) tese_carlos_davi_santos_e_silva.pdf: 1996582 bytes, checksum: f5e5507222353ab43be89856ea18958b (MD5) / Made available in DSpace on 2017-06-14T20:55:21Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) tese_carlos_davi_santos_e_silva.pdf: 1996582 bytes, checksum: f5e5507222353ab43be89856ea18958b (MD5) Previous issue date: 2015-09-25 / Sem bolsa / Devido às diferenças de altitude entre as diversas regiões de cultivo de macieira no Brasil, conhecer as respostas fisiológicas das plantas nessas diferentes condições constituem-se questões relevantes a serem estudadas, uma vez que a altitude pode influenciar a interação das plantas com diversos fatores abióticos e bióticos, afetando o crescimento e o desenvolvimento das mesmas. Este trabalho teve por objetivos caracterizar a densidade de estômatos e as trocas gasosas em folhas, a dinâmica do teor de amido e da relação C/N em ramos do tipo brindila, bem como a produção e qualidade de frutos de macieiras cultivadas em três diferentes altitudes. O experimento foi conduzido em pomares localizados nas altitudes de 1.000, 1.200 e 1.400 metros, nos ciclos 2012/2013, 2013/2014 e 2014/2015. Utilizou-se as cultivares de macieiras (Malus domestica Borkh.) Fuji Suprema e Imperial Gala, com 7-8 anos de idade, enxertadas sobre M-9 e 2.500 plantas ha-1. Durante os três ciclos produtivos foram avaliados o conteúdo de amido e a relação C/N em ramos do tipo brindila. Durante os ciclos 2013/2014 e 2014/2015 foram avaliadas as trocas gasosas em folhas de brindilas, o índice SPAD, produção e qualidade de frutos. Em dezembro de 2013 foi determinada a densidade de estômatos. Cada cultivar foi avaliada de forma independente e adotou-se o delineamento inteiramente casualizado com três tratamentos (1.000m, 1.200m e 1.400m de altitude) e sete repetições, sendo cada repetição representada por uma planta. Realizou-se a análise de variância dos dados e as médias foram comparadas pelo teste de Scott- Knott (p≤5). A cultivar Fuji Suprema apresentou densidade estomática crescente de acordo com a altitude, porém nenhuma alteração significativa foi identificada na cultivar Imperial Gala. De maneira geral, as diferenças nos parâmetros de trocas gasosas registradas entre cada altitude, dentro de cada época de avaliação, variaram principalmente em função das condições climáticas locais. A eficiência instantânea de carboxilação, no entanto, tendeu a ser maior com o aumento da altitude nas plantas de ambas as cultivares. Similar resposta foi identificada para o teor de amido nas brindilas, de ambas cultivares, porém foi observado que quanto maior a carga de frutos, menor foi o teor de amido nos ramos até a colheita. No geral o teor de amido e a relação C/N apresentaram uma relação diretamente proporcional com as variações na altitude dos pomares. A ocorrência de mancha de Glomerella na ‘Imperial Gala’ cultivada a 1.000m influenciou essas duas últimas variáveis. Os frutos de ambas as cultivares estudadas tenderam apresentar melhor qualidade nas maiores altitudes. Isso ficou evidenciado quando comparados a firmeza de polpa e o teor de sólidos solúveis totais. / Due to differences in altitude between the various apple-growing areas in Brazil it is extremely important to know the physiological responses of plants under those different conditions, because altitude can influence the interaction of plants with various biotic and abiotic factors affecting their growth and development. The objective of this work was to characterize the density of stomata, gas exchange in leaves, starch content dynamics, C/N ratio in brindila-type branches, and production and quality of apple tree fruits grown at three different altitudes. The experiment was conducted in orchards located at altitudes of 1000, 1200 and 1400 meters, 2012/2013, 2013/2014 and 2014/2015 cycles. We used apple trees (Malus domestica Borkh) Fuji Suprema and Imperial Gala cultivars that were 7-8 years old, grafted on M-19, and 2500 plants ha-1. During the three production cycles we evaluated the starch and C/N ratio in brindila-type branches. Gas exchange in brindilas leaves, SPAD index, fruits production and quality were evaluated during 2013/2014 and 2014/2015 cycles. Stomata density was determined in December 2013. Each cultivar was evaluated independently and we adopted the completely randomized design with three treatments (1000m, 1200m, and 1400m altitude) and seven repetitions, each one represented by one plant. We performed analysis of variance (ANOVA) to the data set, and means were compared by Scott-Knott test (p≤5). Fuji Suprema cultivar showed growing stomata density in accordance with altitude, but no significant change was identified in Imperial Gala cultivar. In general, differences in gas exchange parameters recorded between each altitude, in each evaluating time varied mainly depending on local weather conditions. The instantaneous carboxylation efficiency, however, tended to be higher in both plants cultivars with increasing altitude. Similar response was identified for starch content in brindilas of both cultivars, however we observed that the higher the fruit load, the lower the starch content in the branches to harvest. In general, starch content and C/N ratio showed a directly proportional relationship with variation in altitude of the orchards. The occurrence of Glomerella spot in ‘Imperial Gala’ grown at 1000m influenced those latter two variables. The fruits of both cultivars studied tended to have better quality at a higher altitude. It was evidenced when the pulp firmness and total soluble solid content were compared.

Submitted by Natalie Mendes (nataliermendes@gmail.com) on 2015-08-04T01:30:32Z No. of bitstreams: 1 CRIS TESE FINAL.pdf: 3970188 bytes, checksum: 37240b01333f3a3c2c98ce2597450f53 (MD5) / Made available in DSpace on 2015-08-04T01:30:32Z (GMT). No. of bitstreams: 1 CRIS TESE FINAL.pdf: 3970188 bytes, checksum: 37240b01333f3a3c2c98ce2597450f53 (MD5) Previous issue date: 2015-03-13 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The life cycle of a seed plant involves subsequent stages of development including seed formation, germination and seedling establishment. Together these stages represent the critical phase of intersection between two generations and are characterized by deep cytological, morphological, metabolic and physiological changes. Jatropha curcas L. (Euphorbiaceae) is popularly known as physic nut and produces seeds rich in oil with properties that allow its use in various industries, including the production of biodiesel. This study aimed to advance on the understanding of morphophysiological patterns and elucidate morphoanatomical adaptations involving embryogenesis, maturation, germination and seedling growth in J. curcas. Therefore, it was initially analysed and described the morphophysiological profile based on 13 stages of development and maturation associated to color of the fruit exocarp and seed coat, and description of the structures present at each stage (Chapter 1). Analysis of microtubular cytoskeleton configurations during embryogenesis showed cell cycle activity by the presence of cortical and mitotic microtubules during histodifferentiation and organogenesis, whilst it was possible to characterize a new organogenetic profile of embryogenesis revealed by the presence of a multimeristematic radicle and stomata in embryos of J. curcas seeds (Chapter 2). The multimeristematic embryos formed by a central apical meristem and four lateral meristems interconnected by a complex vascular system have revealed a new model of root formation during seed germination and seedling development, in which there is simultaneous protrusion of a larger main root and four smaller adventitious roots, all growing at the same time during the formation of the seedling root system (Chapter 3). The stomata occurred in the radicle-hypocotyl transition area, exhibited different sizes and ontogenic phases and short lifespan by degenerating during seedling development. This demonstrates it?s functioning as restricted to the simultaneous growth stage of the five roots during germination, apparently due to high demand in gas exchange and energy metabolism, and a likely evolution onto the lenticels present in the stem of this species (Chapter 4). / O ciclo de vida de uma planta com sementes envolve est?dios subsequentes de desenvolvimento, como a forma??o da semente, a germina??o e o estabelecimento da pl?ntula. Essas etapas juntas representam a fase cr?tica de interse??o entre duas gera??es e s?o caracterizadas por profundas mudan?as citol?gicas, morfol?gicas, metab?licas e fisiol?gicas. Jatropha curcas L. (Euphorbiaceae) conhecida popularmente como pinh?o-manso, produz sementes ricas em ?leo com propriedades e aplica??es em diversos setores industriais, incluindo a produ??o de biodiesel. O presente estudo teve como objetivo caracterizar padr?es morfofisiol?gicos e elucidar adapta??es morfoanat?micas envolvendo a embriog?nese, matura??o, germina??o e o crescimento de pl?ntulas de J. curcas. Para tanto, foi inicialmente analisado e descrito o perfil morfofisiol?gico baseado em 13 est?dios de desenvolvimento e matura??o, associados ? colora??o do exocarpo do fruto e do tegumento das sementes e descri??o das estruturas presentes em cada est?dio (Cap?tulo 1). A an?lise das configura??es do citoesqueleto microtubular durante embriog?nese evidenciou atividade do ciclo celular por meio da presen?a de microt?bulos corticais e mit?ticos durante a histodiferencia??o e organog?nese. Foi poss?vel caracterizar um novo padr?o organogen?tico de embriog?nese revelado pela presen?a de rad?cula multimeristem?tica e de est?matos em embri?es de sementes de J. curcas (Cap?tulo 2). Os embri?es multimeristem?ticos, providos de um meristema apical central e quatro meristemas laterais, revelaram um novo modelo de forma??o de sistema radicular durante a germina??o de sementes e desenvolvimento de pl?ntulas, em que h? protrus?o simult?nea de uma raiz principal maior e quatro ra?zes advent?cias menores, todas crescendo ao mesmo tempo, durante a forma??o inicial do sistema radicular da pl?ntula (Cap?tulo 3). Os est?matos ocorrem na ?rea de transi??o hipoc?tilo-rad?cula e exibem diferentes tamanhos e fases ontog?nicas. Estas estruturas apresentaram um curto per?odo de vida, degenerando-se durante o desenvolvimento da pl?ntula, sugerindo seu funcionamento restrito ? etapa de crescimento simult?neo das cinco ra?zes durante a germina??o, aparentemente devido ? alta demanda em trocas gasosas e metabolismo energ?tico, e uma prov?vel evolu??o para as lenticelas presentes no caule desta esp?cie (Cap?tulo 4).

Aloe L. (Asphodelaceae) is a monocotyledonous group of considerable popularity among succulent plant collectors and with a long history of medicinal use. It comprises ca. 500 species occurring throughout Africa, the Arabian Peninsula and western Indian Ocean islands. The first comprehensive ethnobotanical study of Aloe (excluding the cultivated A. vera) was undertaken using the literature as a surrogate for data gathered by interview methods. Over 1400 use records representing 173 species were collated, the majority (74%) of which described medicinal uses, including species used for natural products. In southern Africa, 53% of approximately 120 Aloe species in the region are used for health and wellbeing. Consensus ratios indicated that the uses of Aloe spp. for medicine and pest control are of the greatest biocultural importance. Utility has contributed to the recognition of diversity, taxonomic complexity, and conservation concerns, in Aloe. A systematic evaluation of the problematic maculate (spotted) species complex, section Pictae, was undertaken. New sequences were acquired of the nuclear ribosomal internal transcribed spacer (ITS), chloroplast trnL intron, trnL–F spacer and matK gene in 29 maculate species of Aloe. A well supported monophyletic (holophyletic) maculate group was recovered in phylogenetic trees of comparable topology generated by parsimony analysis and Bayesian inference. A representative of the related section Paniculatae, A. striata, was recovered in the maculate group, whereas doubtful maculate species with unusual floral morphology (A. leptosiphon and A. suffulta) comprised a sister group. Analogous patterns were identified in chemosystematic and comparative morphological studies of 34 and 36 maculate species, respectively, and insights were gained into interspecific relationships. The flavonoids isoorientin and isovitexin, and a new C-glycosylanthrone, 6′-malonylnataloin, were characterised using hyphenated chromatographic techniques and nuclear magnetic resonance (NMR) spectroscopy. Leaf surface sculpturing, stomata and lobes surrounding the epistomatal pore observed under a scanning electron microscope (SEM) are of potential taxonomic significance. Available evidence indicates that floral characters, namely a basally swollen perianth with constriction above the ovary, are of greater significance than maculate leaves as synapomorphies for section Pictae. An evolutionary hypothesis for section Pictae excludes marginal maculate species with unusual flowers. / Thesis (PhD)--University of Pretoria, 2009. / Plant Science / unrestricted