Orientador: Paulo A. Martins Leal / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-07T02:06:41Z (GMT). No. of bitstreams: 1 Scaranari_Ciro_D.pdf: 4375189 bytes, checksum: be0a12907f91b0a3e056a9e6f4ff67c5 (MD5) Previous issue date: 2006 / Resumo: passar por um período de aclimatação, pois não realizam eficientemente a absorção de luz, água e nutrientes. A aclimatação deve ser feita em casas de vegetação, onde as condições de umidade relativa do ar e luminosidade são favoráveis a um endurecimento gradual das plântulas, período este que, para bananeira, se divide em dois estágios: o primeiro, denominado pré-aclimatação ou berçário, no qual as plântulas permanecem sob reduzida intensidade luminosa e elevada umidade relativa do ar até atingirem altura mínima de 10 cm e o segundo, a aclimatação propriamente dita, sob maior intensidade de luminosidade até que atinjam padrões comerciais. O presente trabalho estudou o desenvolvimento de mudas durante o segundo estágio da aclimatação sob diferentes condições de luminosidade (plena, 70, 50 e 30% de superfície de cobertura com malha vermelha e 50% com malha preta, ambas sob filme plástico transparente de 100 µm) associado a períodos de aclimatação (3, 6 e 9 semanas), em ambientes sob condições favoráveis de temperatura (ao redor de 28ºC, com mínimas a 18ºC e máximas a 34ºC), umidade relativa (acima de 75%), nutrição e irrigação controladas, tendo como variáveis físicas da planta, a altura e o diâmetro do pseudocaule, a área foliar, o número de folhas, o comprimento das raízes e a massa da matéria fresca e seca, e como bioquímicas, a quantificação de pigmentos, de açúcares e do rendimento quântico da fotossíntese obtido por meio da fluorescência da clorofila. Após cada período, as plantas foram submetidas a ensaios de desenvolvimento em condições de campo por 7 semanas, sendo avaliadas para as mesmas variáveis. Quanto aos parâmetros ambientais, os resultados indicam controle satisfatório de temperatura e umidade relativa do ar nos ambientes oferecendo as condições requeridas pela planta embora tenham sido observadas diferenças significativas entre eles. As malhas vermelhas apresentam transmitâncias diferenciadas ao longo do espectro da radiação fotossinteticamente ativa e os resultados mostram maiores reduções na faixa RFA para estas, independente do horário, insolação e estação do ano. Na comparação entre as médias, cada tratamento recebeu pontuações obedecendo à ordenação hierárquica de desempenho verificada em cada avaliação (casas de vegetação e campo), segundo critérios de classificação estatística, onde considera-se o número de tratamentos estatisticamente inferiores e superiores. Na ordenação estatística, o uso de malha preta com 50% de sombreamento associado ao período de 9 semanas foi o que propiciou melhores condições, tanto no verão quanto no inverno. Visando a redução para 6 semanas, o uso alternativo de tela de malha vermelha com 70% de sombreamento produz efeitos equivalentes ao da malha preta com 50% em 9 semanas, apenas para condições de verão. Medidas paralelas utilizando o medidor portátil de clorofila SPAD-502 foram efetuadas simultaneamente às determinações analíticas deste parâmetro, verificando-se correlações positivas significativas da regressão entre o conteúdo de clorofila total e a leitura do equipamento. De acordo com o modelo da classificação estatística, verificou-se que as maiores pontuações envolvendo todos os parâmetros estudados coincidiram com as maiores pontuações obtidas pela leitura SPAD, recaindo na maioria das situações no ambiente com malha preta, já descrito como o de melhor desempenho entre todos. Assim, o uso deste equipamento pode vir a se constituir em importante ferramenta para avaliação auxiliar e expedita de plantas de bananeira sob aclimatação, requerendo, para tanto, mais estudos que visem o estabelecimento de modelos que melhor expliquem esta relação / Abstract: acclimatization, because it does not operate light, water and nutrient absorption in an efficient way. The acclimatization must be done at a greenhouse, where temperature, light and air humidity are adequate to a gradual hardening of plantlets. The first period lasts until the plantlet reaches 10 cm height and is named pre-acclimatization or nursery, being characterized by low light intensity and high relative air humidity. The acclimatization phase ends when plants reach commercial standards under a higher light intensity. In this study, banana plantlets development was evaluated during acclimatization under different light conditions (full, 70%, 50% and 30% of a covered surface with a red mesh and 50% with a black mesh, both under a transparent plastic film of 100 µm), average temperature of 28ºC (minimum 18ºC and maximum 34ºC), above 75% relative air humidity and controlled nutrition and irrigation. Physical parameters as height, pseudostems¿s diameter, number and leaves area, root¿s length and fresh and dry biomass, and also physiological data as pigment, sugars and quantum efficiency obtained by chlorophyll¿s fluorescence were taken after 3, 6 and 9 weeks and after 7 weeks of transplantation to field conditions. Treatments were hierarchically graded according to their statistic¿s classification. Temperature and relative air humidity were adequate for plant¿s development, although significant differences were observed between the different environment conditions. The presence of red mesh resulted in different transmittances along the photosynthetically active radiation specter, showing a greater reduction on the PAR zone, independently of time, insulation and year season. Combined results indicate superior results of the black 50% mesh for a acclimatization period of nine weeks, either in the summer as in the winter season. Pursuing a time reduction to a six week period, the use of a red 70% mesh showed similar results as the black 50% mesh for nine weeks, in summer conditions. Chlorophyll contents were also measured with a SPAD-502 and these results, when ordered by values, gave a similar ranking as all other parameters taken together. According to the statistical classification model, it was verified that SPAD can be used as an easy and fast tool to evaluate banana plants under acclimatization / Doutorado / Construções Rurais e Ambiencia / Doutor em Engenharia Agrícola

Made available in DSpace on 2014-08-20T13:59:15Z (GMT). No. of bitstreams: 1 dissertacao_cibele_merched_gallo.pdf: 638641 bytes, checksum: 82fbd49520aa928426c112de64c9a625 (MD5) Previous issue date: 2012-02-15 / Although fruiting plants can be propagated by several methods, commercial seedlings of Prunus are obtained by grafting a scion on a rootstock. In Rio Grande do Sul State, because of the proximity of the canning industry, the rootstocks originate from the disposal pits of late maturing cultivars, allowing the occurrence of varietal mixtures, and consequently, the formation of orchards with uneven plants. On the other hand, vegetative propagation leads to the formation of uniform plants, because they keep the characteristics of the mother-plant. This propagation may be made by several methods, for example, micropropagation. Thus, to develop protocols for vegetative propagation will contribute to the production of seedlings of Prunus spp. in southern Brazil. The aim of this work was to optimize in vitro multiplication and rooting, and the acclimatization of shoots from the rooting medium with rootstock Mr. S. 2/5.This work was divided into two chapters, one on the in vitro multiplication, and the second refers to in vitro rooting and acclimatization. In the first chapter, composition of salts, culture medium pH, source and concentration of carbohydrate, and concentration of IBA were tested. In the second chapter, the objective was to evaluate the effect of IBA concentration, and the permanence time of the shoots in the culture medium, in vitro rooting, and their survival during acclimatization phase. At the multiplication stage, the explants cultivated in MS medium, pH 5.2, showed a higher number of shoots. However, the source and concentration of carbohydrate had no influence on number and length of the shoots formed. In relation to IBA concentrations, supplemented mediums with 0.06mgL-1 increased formation of shoots, but had no significant influence on their length. With respect to in vitro rooting phase and acclimatization, shoots cultivated in a culture medium with 1.6mgL-1 IBA, during 12 days, showed high percentage of rooting, approximately 90%, as well as higher percentage of surviving plants in the acclimatization phase. / Apesar das plantas frutíferas serem propagadas por vários métodos, as mudas comerciais de prunáceas são obtidas por meio da enxertia de uma cultivar copa sobre um porta-enxerto. No Rio Grande do Sul pela proximidade das indústrias de conserva, os porta-enxertos são originários a partir do descarte dos caroços de cultivares de maturação tardia, aspecto este que permite a ocorrência de misturas varietais e consequentemente a formação de pomares com plantas desuniformes. Por outro lado, a propagação vegetativa leva à formação de plantas uniformes, pois mantém as características da planta matriz, podendo esta ser realizada por diversos métodos, como por exemplo, a micropropagação. Assim, desenvolver protocolos de propagação vegetativa irá contribuir no processo de produção de mudas de prunáceas na região Sul do Brasil. Portanto, o objetivo do presente trabalho foi otimizar a multiplicação e o enraizamento in vitro, bem como a aclimatização das brotações provenientes do meio de enraizamento com o porta-enxerto Mr. S. 2/5 . Para tal, o trabalho foi dividido em dois capítulos, um sobre a multiplicação in vitro e o segundo referente ao enraizamento in vitro e aclimatização. No primeiro capítulo foram testados a composição de sais, o pH do meio de cultura, a fonte e a concentração de carboidrato e a concentração de AIB. No segundo capítulo, objetivou-se avaliar o efeito da concentração de AIB e o tempo de permanência das brotações no meio de cultura, sobre o enraizamento in vitro e a sobrevivência dessas na fase de aclimatização. Na etapa de multiplicação, explantes cultivados em meio MS com pH 5,2 apresentaram o maior número de brotações. Entretanto, a fonte e a concentração de carboidrato não exerceram influência sobre o número e o comprimento das brotações formadas. Já, com relação às concentrações de AIB, meios suplementados com 0,06 mg L-1 apresentaram maior formação de brotações, porém sem influência significativa para o comprimento destas. No que diz respeito à fase de enraizamento in vitro e de aclimatização, brotações cultivadas em meio de cultura com 1,6 mg L-1 de AIB por 12 dias, apresentaram alta percentagem de enraizamento, aproximadamente, 90%, bem como maior percentagem de plantas sobreviventes na fase de aclimatização.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Peltophorum dubium is native forest species of Brazil endowed with ecological importance for the recovery of degraded areas and economical for timber purposes. The seeds of this species have low and irregular germination if they are not subjected to treatments to overcome dormancy. However, there are few studies that allow for the vegetative propagation of the species. As a result, the present study aimed to evaluate the formation of roots in shoots of P. dubium applying the techniques of micropropagation and minicutting and acclimatization of plants produced by these techniques. For rooting in vitro micropropagated shoots were subjected to treatments where different culture media were tested, with addition of 30 g L-1 vermiculite, combined with the nutrient media MS, MS/2, WPM, WPM/2 and changes in concentrations of auxin IBA (0, 5, 10 or 20 μM) and sucrose (0, 15 or 30 g L -1) in the presence or absence of agar (0 or 7g L-1) arranged in different tests. The results indicated that the best combination for root formation in vitro shoots of Peltophorum dubium is the use of nutritional WPM/2 without addition of sucrose and auxin, with 7 g L- 1 agar. This condition was still allowing the best performance of the plants during acclimatization in vitro. For rooting of shoots via minicutting, cuttings 3-7 cm apical portion of rooted shoots of seminal origin were used. Root formation after the cuttings are subjected to immersion in solution with 0, 1.000, 2.000 or 4.000 mg L- 1 IBA, from different collections and during 30, 60 or 90 days in a greenhouse with controlled conditions was evaluated for root induction. Rooting in cuttings occurred even without the use of IBA, after successive collections. However, it was increased with the use of up to 2.000 mg L-1 auxin the period of 60 days being sufficient for the formation of roots takes place. The seedlings showed good performance during acclimatization, indicating that the technique is feasible for minicutting plants production Peltophorum dubium. / Peltophorum dubium é uma espécie florestal nativa do Brasil dotada de importância ecológica para fins de recuperação de áreas degradadas e econômica, para fins madeiráveis. As sementes desta espécie apresentam germinação baixa e irregular se não forem submetidas a tratamentos para superação de dormência. Em virtude da carência de estudos que viabilizem a propagação vegetativa da espécie e considerando a natural recalcitrância em relação à rizogênese nesse processo, o presente trabalho teve como objetivo avaliar a rizogênese in vitro e ex vitro em brotações de P. dubium aplicando-se as técnicas de micropropagação e de miniestaquia, bem como a aclimatização das mudas produzidas por meio destas técnicas. Para a rizogênese in vitro, brotações micropropagadas foram submetidas a tratamentos em que foram testados diferentes meios de cultivo, com acréscimo de 30 g L-1 de vermiculita, combinados aos meios nutritivos MS, MS/2, WPM, WPM/2 e alterações nas concentrações da auxina ácido indolbutírico - AIB (0, 5, 10 ou 20 μM) e sacarose (0, 15 ou 30 g L-1), na presença ou ausência de ágar (0 ou 7 g L-1), arranjados em diferentes ensaios. Os resultados indicaram que a melhor combinação para a rizogênese in vitro em brotações de Peltophorum dubium é a utilização do meio nutritivo WPM/2, na ausência de sacarose e da auxina, porém com 7 g L-1 de ágar. Essa condição foi, ainda, a que permitiu o melhor desempenho das mudas durante a aclimatização in vitro. Para a rizogênese em brotações via miniestaquia, foram utilizadas miniestacas, de 3 a 7 cm, isoladas da porção apical de brotações de minicepas de origem seminal. Foi avaliada a formação de raízes após as miniestacas serem submetidas à imersão em solução contendo 0, 1.000, 2.000 ou 4.000 mg L-1 de AIB, oriundas de diferentes coletas e permanecendo por 30, 60 ou 90 dias em casa de vegetação com condições controladas adequadas à indução de raízes. A rizogênese nessas miniestacas ocorreu mesmo sem a utilização de AIB, ao longo das sucessivas coletas. No entanto, foi incrementada com a utilização de até 2.000 mg L-1 da auxina, sendo suficiente o período de 60 dias para que ocorra a formação de raízes. As mudas apresentaram bom desempenho durante a aclimatização, indicando que a técnica de miniestaquia é viável para a produção de mudas de Peltophorum dubium.

Acclimatization is a process which occurs as a result of repeated mild increases in core temperature, which allows an organism to carry out increased work in the heat due to better heat dissipation (Moseley, 1997). In order to prevent the occurrence of heat illness, it is necessary for individuals who perform work in hot, humid environments to undergo acclimatization. Exposure to different types of stimuli, such as heat exercise and oxidative stress, results in the formation of proteins in the cells which are known as heat shock protein (HSP) (Powers et al, 2001). The main function of HSP is to act as molecular chaperones. Specifically, the 70 kDa HSP, known as Hsp70, play an important part in cellular protection and adaptation during and following exposure to stressful events. Two prominent members of the Hsp70 family are Hsp72, which is the inducible form of Hsp70, and Hsp73, which is the constitutively synthesized form of the protein. Acquisition of thermotolerance in vitro in Chinese hamster fibroblast cells is accompanied by increased Hsp72 levels during a heating episode, indicating that Hsp72 tends to target proteins which have been damaged by a stress situation more than Hsp73 (Li and Werb, 1982). A number of different hsp70 genes are found, which include hsp70-1, hsp70-2 (3¢utr and pst I) and hsp70-hom (Milner and Campbell, 1990). Both the hsp70-1 and hsp70-2 genes encode the primary heat-induced Hsp70 protein as an identical protein product (Hunt and Morimoto, 1985). Following heat shock, no increase in the hsp70-hom mRNA levels is observed (Milner and Campbell, 1990). The use of the Hsp70 protein and hsp70 gene polymorphisms as markers of acclimatization were investigated by subjecting twenty-two individuals to exercise in a hot, humid environment. These individuals were exposed to an initial heat stress, where they participated in a step test at an external work rate of 70 W, followed by participation in an acclimatization program which involved exercising at various combinations of 35 W and 70 W of the external work rate. After acclimatization, the individuals were exposed to a second heat stress, identical to the initial heat stress. The Hsp70 levels both before and after acclimatization were determined in response to heat stress in blood serum by means of the StressXpress ELISA Kit (Stressgen Biotechnologies) and in human monocytes by means of Western blots, using a mouse antiñHsp70 monoclonal primary antibody (Stressgen Biotechnologies) and a goat antiñmouse IgG (H+L) peroxidase conjugated secondary antibody. The hsp70 gene polymorphisms were determined by means of polymerase chain reaction (PCR), using primers specific to the hsp70-1, hsp70-2 (3¢utr), pst I and hsp70-hom genes, so that the genotype combinations for each individual were determined. Blood type was also assessed. It was found that the basal serum Hsp70 levels in individuals who exhibited the ability to acclimatize decreased in response to the acclimatization program, which allowed more Hsp70 to be induced in response to the second heat stress compared to the initial heat stress. The individuals who were unable to acclimatize showed increased basal serum Hsp70 levels in response to acclimatization, which prevented these individuals from inducing high Hsp70 levels in response to the second heat stress. The Hsp70 induced in the monocytes during this program followed the same pattern in both the individuals able to acclimatize and those who were unable to acclimatize, and can therefore not be used as a marker of acclimatization. For the female participants, the current menstrual phase of each woman had to be taken into account, as this had an affect on the core temperature and therefore influenced the division of the female participants into their respective groups. These were the group of individuals who demonstrated the ability to acclimatize or the group of individuals who were unable to acclimatize. The use of oral contraceptives also had to be taken into account, as this too had an influence on the core temperature and therefore also affected the division of the individuals into the group who demonstrated the ability to acclimatize or those who were unable to acclimatize. Cyclic changes during the menstrual cycle may have also changed the Hsp profile. Regarding the hsp70 gene polymorphisms, the A/A, P2 P2 and A1 A1 genotype combination was not present in any of the individuals who were unable to acclimatize, however six of the individuals who showed the ability to acclimatize possessed this genotype combination. The level of induced Hsp70 levels present in the serum of individuals able to acclimatize and the presence or absence of the A/A, P2 P2 and A1 A1 genotype combination therefore have the potential to be used as markers of acclimatization. / Dr. M. Cronje

The spleen has been shown to contract in apneic situations in humans as well as in other diving mammals, expelling its stored red blood cell content into circulation. This natural blood boosting may increase the circulating hemoglobin concentration (Hb) by up to 10%, which would enhance the oxygen carrying capacity and likely increase performance. However, the triggers of this response in humans have not been fully clarified. Study I was therefore focused on the effect of hypoxia as a trigger of spleen contraction. It was found that 20 min of normobaric hypoxic breathing evoked a substantial reduction in spleen volume showing that hypoxia is an important trigger for spleen contraction. Knowing the role of hypoxia, Study II compared two different hypoxic situations – a 2 min apnea and 20 min normobaric hypoxic breathing – which resulted in the same level of arterial hemoglobin desaturation. Apnea evoked a twice as great spleen volume reduction, implying that variables other than hypoxia were likely involved in triggering spleen contraction. This may be hypercapnia which is present during apnea but not during normobaric hypoxic breathing. Study III therefore investigated the effects of breathing gas mixtures containing different proportions of CO2 prior to maximal apneas. Pre-breathing mixtures with higher percentages of CO2 resulted in greater spleen contraction, thus demonstrating hypercapnia's likely role as a trigger in addition to hypoxia. Study IV explored whether an all-or-nothing threshold stimulus for triggering spleen contraction existed, or if contraction was graded in relation to the magnitude of triggering stimuli. Exercise was therefore performed in an already hypoxic state during normobaria. Rest in hypoxia produced a moderate spleen volume reduction, with an enhanced spleen contraction resulting after hypoxic exercise, with a concomitant increase in Hb. This implies that spleen contraction is a graded response related to the magnitude of the stimuli. This could be beneficial in environments with varying oxygen content or work loads. Study V examined the possibility that spleen contraction is part of the acclimatization to altitude, during an expedition to summit Mt Everest. The long-term high altitude exposure, combined with physical work on the mountain, had no effects on resting spleen volume but resulted in a stronger spleen contraction, when provoked by apnea or exercise. This indicates that acclimatization to altitude may enhance the contractile capacity of the spleen, which may be beneficial for the climber. From these studies I concluded that hypoxia is an important trigger for spleen contraction but that hypercapnia also contributes in apneic situations. The spleen contraction likely provides a graded expulsion of erythrocytes in response to these stimuli, causing a temporary increase in gas storage capacity that may facilitate activities such as freediving and climbing. The storage of erythrocytes during rest serves to reduce blood viscosity, which would also be beneficial for the climber or diver. The human spleen contraction appears to become stronger with acclimatization, with beneficial effects at altitude. Such an upgraded response could be beneficial both in sports and diseases involving hypoxia.

Anaerobic digestion can be used to sustainably treat the organic byproducts of the biodiesel process (crude glycerol and biodiesel wastewater) while generating a renewable natural gas to be used for heating or electricity generation. The purpose of this thesis was to (1) investigate the possibility of co-digestion of biodiesel byproducts without use of external substrates or pretreatment and (2) assess the impact of various acclimatization rates on the stability and efficiency of such a system. Two inocula (effluent from a wastewater treatment plant digester and from an agro-industrial waste digester) and two acclimatization rates were studied. The results showed that co-digestion of crude glycerol and biodiesel wastewater at high organic loading rates(up to 6.8 g COD L-1day-1)is possible without addition of other substrates or pretreatment.Thecumulative biogas production of the digesters using inoculum from the agro-industrial waste digester was statistically greater than the digesters using the wastewater treatment plant digester, indicating that similar inoculum could be useful for additional experiments.In addition,maximum efficiency due to a slower rate of acclimatization was higher for both inocula, up to a maximum average daily biogas yield of 621 mL biogas g-1COD added.Finally, comparison of two methods for measuring gas production (mass difference and volumetrically using a syringe) revealed a reasonable correlation(R2= 0.97)between the methods. Additional validation could lead to use of the mass difference method as a validation method or an alternative gas production measurement method.

Heat stress is an environmental and occupational hazard exacerbated by climate change. Rural populations and sub-populations continue to experience disproportionate risks of heat-related impacts due to their low adaptive capacities in terms of infrastructure, information and other resources which are critical in dealing with heat. The study goals were to determine heat-related mortality risks in rural populations globally, explore the contribution of the outdoor work environment and other factors in association with occupational heat-related illnesses (HRI), and assess the risk of heat stress among crop workers using the Wet Bulb Globe Temperature (WBGT). Published peer-reviewed scientific literature on heat-related mortality in rural areas was used to assess heat-related risks among rural populations worldwide. Excess risks of both all-cause and cardiovascular mortalities were found although temperature had a stronger impact on cardiovascular deaths than for all-cause mortality. Also, using cross-sectional data from health screening clinics conducted during the summers of 2014, 2015, and 2016, a total of 425 patient encounters were analyzed using chi-square and logistic regression analyses to determine the role of the outdoor work environment and other factors associated with heat stress. As expected, the outdoor work environment was significantly associated with HRI. Out of the total of 67 HRI cases that were self-reported or diagnosed, 82% (55 cases) worked outdoors. There were nonsignificant elevations in HRI prevalence reported in males, workers below 40 years of age, individuals who have worked in agriculture for ten years or less, and those trained on heat safety. Further, a comprehensive evaluation of heat stress among crop workers was conducted using the four thermal climate factors-- air temperature, humidity, wind speed and solar radiation-- as well as work load and clothing factors. It found both acclimatized and non-acclimatized workers at risk of HRI. Regression analysis revealed that HRI prevalence was strongly correlated with the daily maximum WBGT (R2= 0.89; p= 0.03). Thus, effective heat safety precautions are needed, in addition to acclimatization, to protect vulnerable outdoor workers.

Orientador: Luiz Fernando Rolim de Almeida / Resumo: O desenvolvimento das plantas é controlado por vários fatores ambientais dentre os quais a água, cujo papel vital determina o sucesso no estabelecimento vegetal. Embora as intervenções abióticas as quais estão sujeitas ao longo de seu desenvolvimento possam prejudicá-las, os eventos de estresse anteriores podem induzir seu metabolismo contra posteriores, influenciando respostas. Memória de estresse envolve múltiplas modificações em níveis fisiológicos, proteômicos, transcricionais e mecanismos epigenéticos em plantas em resposta às essas mudanças no ambiente. Neste estudo, sugeriu-se a hipótese de que as plantas de sorgo previamente expostas a ciclos de défice hídrico terão melhor desempenho fisiológico do que as que nunca enfrentaram esta condição, quando ambos grupos estão sujeitos à baixa disponibilidade de água. Este trabalho propôs identificar algumas das possíveis contribuições fisiológicas para com o desempenho fotoquímico de indivíduos da espécie Sorghum bicolor (L.) Moench submetidos a dois eventos de défice hídrico, em comparação com indivíduos expostos a apenas um evento, além do grupo controle mantido sob irrigação. As respostas fisiológicas observadas em plantas submetidas a défice hídrico recorrente indicam ajustes fisiológicos distintos das plantas do grupo submetido a esta condição apenas uma vez. Os resultados de relações hídricas, taxas fotossintéticas e conservação do aparato fotoquímico sugerem que experiência de estresse anterior pode desenvolver memória ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The development of plants is controlled by several environmental factors including water, whose vital role determines success in plant establishment. Notwithstanding the abiotic stresses that are subject throughout their development can harm them, stress events earlier tend to induce metabolism against further tensions in order to improve responses. Stress memory involves multiple changes in physiological, proteomic, transcriptional levels and epigenetic mechanisms in plants in response to these changes in the environment. In this study, the hypothesis was suggested that sorghum plants previously exposed to water deficit cycles will have a better physiological performance than those that never faced this condition, when both groups are subject to low water availability. This work proposed to identify some of the possible physiological contributions to the photochemical performance of individuals of the species Sorghum bicolor (L.) Moench submitted to two water deficit events, in comparison with individuals exposed to only one event, in addition to the control group kept under irrigation. The physiological responses observed in plants submitted to recurrent water deficit indicate physiological adjustments different from plants in the group submitted to this condition only once. The parameters of water relations, photosynthetic rates and conservation of the photochemical apparatus suggest that previous stress experience may develop physiological memory. The data suggest that th... (Complete abstract click electronic access below) / Mestre

No description available.

Phenotypic plasticity and local adaptation via genetic change are two major mechanisms of response to dynamic environmental conditions. These mechanisms are not mutually exclusive, since genetic change can establish similar phenotypes to plasticity. This connection between both mechanisms raises the question of how much of the variation observed between species or populations is plastic and how much of it is genetic. In this study, we used a structured population of fire salamanders (Salamandra salamandra), in which two subpopulations differ in terms of physiology, genetics, mate-, and habitat preferences. Our goal was to identify candidate genes for differential habitat adaptation in this system, and to explore the degree of plasticity compared to local adaptation. We therefore performed a reciprocal transfer experiment of stream- and pond-originated salamander larvae and analyzed changes in morphology and transcriptomic profile (using species-specific microarrays). We observed that stream- and pond-originated individuals diverge in morphology and gene expression. For instance, pond-originated larvae have larger gills, likely to cope with oxygen-poor ponds. When transferred to streams, pond-originated larvae showed a high degree of plasticity, resembling the morphology and gene expression of stream-originated larvae (reversion); however the same was not found for stream-originated larvae when transferred to ponds, where the expression of genes related to reduction-oxidation processes was increased, possibly to cope with environmental stress. The lack of symmetrical responses between transplanted animals highlights the fact that the adaptations are not fully plastic and that some level of local adaptation has already occurred in this population. This study illuminates the process by which phenotypic plasticity allows local adaptation to new environments and its potential role in the pathway of incipient speciation.