Orientador: Luiz Fernando Rolim de Almeida / Resumo: Plantas que presenciam a seca podem armazenar informações sobre esta experiência, tal como uma memória ao estresse. As informações adquiridas com a memória do estresse podem ser utilizadas para aumentar a tolerância a futuros eventos de défice hídrico, porém, o crescimento das plantas pode ser limitado. O objetivo deste estudo foi investigar as respostas fisiológicas, bioquímicas e epigenéticas de Sorghum bicolor (L.) Moench durante e após o primeiro e segundo evento de défice hídrico, bem como as vantagens e desvantagens de eventos recorrentes de seca para a tolerância e crescimento. Neste estudo foram utilizados quatro tratamentos que foram: Controle, onde a irrigação foi mantida, Défice Hídrico na Fase Juvenil, onde as plantas foram submetidas a desidratação na fase juvenil seguido de reidratação, Défice Hídrico na Fase Adulta, onde a irrigação foi suspensa na fase adulta seguido de reidratação e Défice Hídrico Recorrente, onde a irrigação foi suspensa na fase juvenil e adulta seguido de reidratação. Foram avaliadas as trocas gasosas, fluorescência da clorofila a, conteúdo relativo de água na folha, densidade estomática, crescimento, enzimas atioxidativas, conteúdo de açucares totais e sacarose e ocorrência da H3K4me3 no gene Sb04g038610. Mesmo com o intervalo entre o primeiro e o segundo evento de seca, o que poderia resultar na remoção da memória do estresse formada no primeiro evento, as respostas fotossintéticas, antioxidativas, morfo-anatomicas e de estado hídrico dem... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Plants that experience drought can store information about this experience, such as a memory of stress. Information acquired with stress memory can be used to increase tolerance to future water deficit events, however, plant growth may be limited. The objective of this study was to investigate the physiological, biochemical and epigenetic responses of Sorghum bicolor (L.) Moench during and after the first and second water deficit event, as well as the advantages and disadvantages of recurrent drought events for tolerance and growth. Four treatments were used: Control, where irrigation was maintained, Water Deficit in the Juvenile Phase, where the plants were submitted to dehydration in the juvenile phase followed by rehydration, Water Deficit in the Adult Phase, where irrigation was suspended in the adult phase followed by rehydration and Recurrent Water Deficit, where irrigation was suspended in the juvenile and adult phases followed by rehydration. Gas exchanges, chlorophyll a fluorescence, relative leaf water content, stomatal density, plant growth, atioxidative enzymes, total sugar and sucrose content and the occurrence of H3K4me3 in the Sb04g038610 gene were evaluated. Even with the interval between the first and second drought events, which could result in the removal of the stress memory, the photosynthetic, antioxidative, morpho-anatomical and water status responses demonstrated that S. bicolor plants showed increased tolerance to drought during recurrent water defici... (Complete abstract click electronic access below) / Doutor

Made available in DSpace on 2014-12-17T15:37:18Z (GMT). No. of bitstreams: 1 EzequielBN_DISSERT.pdf: 1434271 bytes, checksum: ec339b7b0edd61a2480b5454f9c82167 (MD5) Previous issue date: 2013-07-12 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The exposure to stressors produces physiological changes of the organism in order to adapt the individual to the environment. Depending on the type, intensity and duration, stress can affect some cognitive functions, particularly processes of learning and memory. Several studies have also proposed that some level of anxiety would be necessary for memory formation. In this context, memories of previously aversive experiences may determine the manner and intensity with which are expressed fear responses, which explains the great interest in analyzing both anxiety and memory in animals. In addition, males and females demonstrate different reactions in relation to stressful stimuli, showing different levels of anxiety and differences in processing of the acquisition, retention and recall of information. Based on this information, the present study aimed to verify the effect of stress on learning, memory and anxiety behavioral parameters in rats exposed at different types of stressors of long duration (seven consecutive days): restraint (4h/day), overcrowding (18h/day) and social isolation (18h/day) in the different phases of the estrous cycle. Our results showed that the stress induced by restraint and social isolation did not cause changes in the acquisition process, but impaired the recall of memory in rats. Furthermore, it is suggested a protective effect of sex hormones on retrieval of aversive memory, since female rats in proestrus or estrus phase, characterized by high estrogen concentrations, showed no aversive memory deficits. Furthermore, despite the increased plasma levels of corticosterone observed in female rats subjected to restraint stress and social isolation, anxiety levels were unaltered, compared to those various stress conditions. Animal models based on psychological and social stress have been extensively discussed in the literature. Correlate behavioral responses, physiological and psychological have contributed in increasing the understanding of stress-induced psychophysiological disorders / A exposi??o a fatores estressantes promove mudan?as fisiol?gicas adaptativas do organismo ao meio ambiente. Dependendo do tipo, da intensidade e dura??o, o estresse pode afetar algumas fun??es cognitivas, particularmente o processo de aprendizagem e de mem?ria. Alguns estudos tamb?m t?m proposto que a ansiedade, em certa medida, seria necess?ria para que ocorresse a forma??o da mem?ria. Neste contexto, mem?rias de experi?ncias aversivas anteriores podem determinar a maneira e a intensidade com que s?o expressas as respostas de medo, o que justifica o grande interesse em analisar simultaneamente ansiedade e mem?ria em animais. No mais, machos e f?meas apresentam rea??es distintas em rela??o a est?mulos estressores, mostrando diferentes n?veis de ansiedade e diferen?as no processamento da aquisi??o, reten??o e evoca??o de informa??es mnem?nicas. Frente a essas informa??es, o presente estudo teve como objetivo verificar o efeito do estresse em par?metros comportamentais de aprendizagem, mem?ria e ansiedade de ratas submetidas a diferentes tipos de estressores de longa dura??o, (sete dias consecutivos): conten??o (4h/dia), alta densidade populacional (18h/dia) e isolamento social (18h/dia), nas diferentes fases do ciclo estral. Nossos resultados mostraram que o estresse promovido pela conten??o e pelo isolamento social n?o promoveram altera??es no processo de aquisi??o, mas promoveu preju?zos na evoca??o da mem?ria de ratas. Al?m disso, sugere-se um efeito protetor dos horm?nios sexuais sobre a evoca??o da mem?ria aversiva, uma vez que ratas que estavam nas fases proestro ou estro, fase de altas concentra??es plasm?ticas de estr?genos, n?o apresentaram preju?zos na evoca??o dessa mem?ria. No mais, apesar do aumento dos n?veis plasm?ticos de corticosterona observado nas ratas submetidas ao estresse de conten??o e isolamento social, os n?veis de ansiedade permaneceram inalterados frente a essas diferentes condi??es de estresse. Modelos animais baseados em estresse psicol?gico e social t?m sido bastante abordados na literatura. Correlacionar respostas comportamentais, fisiol?gicas e psicol?gicas t?m contribu?do no aumento da compreens?o dos transtornos psicofisiol?gicos envolvidos na resposta de estresse

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / in the soill elevated over the years through anthropogenic actions such as the application of manure and cupping fungicides. As a reflection of these increases the establishment and development of plants grown in these environments can be limited and compromised. Considering the particularities of the different species in resisting and completing their cycle on these conditions this work aimed to evaluate Cu interference on the establishment and initial growth of black oats. The treatments were set up in 5x2 bifactorial, with five concentrations of copper (0, 60, 120, 180, 240 μM) and two sub lots (vigor levels). Thus, analyzes of physiological parameters of black oat seedlings and plants from two sub lots, one artificially aged and another not, both originated from a single lot, were performed. Two experiments were carried out; in the first one, physiological parameters were evaluated which comprise the establishment capacity of the seedlings such as the first count and germination test in B.O.D germinator with controlled conditions; the second one consisted in hydroponic plant cultivation and evaluated physiological parameters of growth, such as length and dry mass of shoot and root, and length and total dry mass. A completely randomized design was adopted in both experiments, being the second one in a split-split plot arrangement. Cu concentrations did not affect seedling establishment capacity, on the other hand the vigor of the seed sub lot affected this ability, with more vigorous (not aged) seeds sub lot having a better establishment. Cu concentrations were detrimental to the initial growth of black oat plants above 60 μM independent of sub lot studied. Seedlings from the non-aged sub lot (high vigor) presented higher initial growth than those from the aged sub lot (low vigor), however acclimatization in the hydroponic system equaled them in root growth and caused an inversion in the total plant growth, being this higher in low vigor sub lot plants. / O cobre (Cu) está entre os metais cujos teores em solo foram elevados ao longo dos anos em decorrência de ações antrópicas como a aplicação de dejetos de animas e fungicidas cúpricos. Como reflexo destes aumentos o estabelecimento e o desenvolvimento das plantas cultivadas nestes ambientes pode ser limitado e comprometido. Consideradas as particularidades das diferentes espécies em resistirem e completarem seu ciclo sobre estas condições pretendeu-se com este trabalho avaliar a interferência do Cu sobre o estabelecimento e crescimento inicial da aveia preta. Os tratamentos foram configurados em bifatorial 5x2, com cinco concentrações de cobre (0, 60, 120, 180, 240 μM) e dois sublotes (níveis de vigor). Nesse sentido, foram realizadas análises dos parâmetros fisiológicos de plântulas e plantas de aveia preta de dois sublotes de sementes, um envelhecido e outro não envelhecido, ambos originados de um único lote. Foram realizados dois experimentos; o primeiro, avaliou parâmetros fisiológicos que compreendem a capacidade de estabelecimento das plântulas, através dos testes de primeira contagem e germinação de sementes em germinador tipo BOD com condições controladas; o segundo experimento, consistiu do cultivo de plantas em sistema hidropônico e avaliou parâmetros fisiológicos de crescimento, como o comprimento e a massa seca de parte aérea e raiz, e comprimento e massa seca total. Foi adotado delineamento inteiramente casualizado em ambos os experimentos, sendo o segundo experimento com arranjo experimental em parcela sub subdividida. As concentrações de Cu não afetaram a capacidade de estabelecimento de plântulas, por outro lado o vigor do sublote de sementes afetou esta capacidade, sendo que melhor estabelecimento foi observado no sublote não envelhecido (alto vigor). O crescimento inicial de plantas de aveia preta foi influenciado negativamente por concentrações de Cu superiores a 60 μM independente do sublote em estudo. Plântulas oriundas do sublote não envelhecido (alto vigor) apresentaram crescimento inicial superior as oriundas do sublote envelhecido (baixo vigor), entretanto a aclimatação em sistema hidropônico as igualou em crescimento de raiz e ocasionou uma inversão no crescimento total da planta, sendo este superior em plantas do sublote de baixo vigor.

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Plants are exposed to the stress of the environment throughout their entire live. They therefore had to develop sophisticated mechanisms to avoid or tolerate stress. In some plants, repeated exposure to stress increases tolerance, which is known as stress memory. The aim of this study is to assess stress memory in terms of oxidative stress level. Content of malondialdehyde (MDA), reactive oxygen species (ROS) and the electrolyte leakage were chosen as markers of oxidative stress. Fresh weight, plant height and water content were also evaluated. The level of oxidative stress was assessed in several genotypes of Solanum tuberosum subspecies, Andigena and Tuberosum. In vitro culture did not work well for the evaluation of stress memory, ex vitro partially did. The content of MDA in 66B was significantly lower than in cv. Lada (Tuberosum) in root (in vitro) and shoot (ex vitro) in control groups as well as during water shortage. Treatment of acclimation-inducing cold before the stress-inducing cold had a variable effect on growth and electrolyte leakage according to the culture conditions. In vitro, the effect on electrolyte leakage in roots of cv. Lada was positive, in leaves of 66B (Andigena) it was negative. In ex vitro, a positive effect was found on electrolyte leakage in 66B leaves, but at the...