Las marismas son ecosistemas valiosos porque, al ocupar zonas transicionales, juegan un rol central en el intercambio de materia orgánica, nutrientes y contaminantes entre las planicies de marea y las aguas adyacentes. En este trabajo se evalúa si la presencia de especies halófitas modifica significativamente los ciclos biogeoquímicos de nutrientes y materia orgánica en el estuario de Bahía Blanca. Se trabajó en dos marismas, Villa del Mar (VM) y Puerto Cuatreros (PC), dominadas por Spartina alterniflora y Sarcocornia perennis, respectivamente, las dos halófitas más abundantes en el sistema. Se midió pH y potencial redox (Eh) en el sedimento y concentraciones de nutrientes disueltos y materia orgánica particulada (MOP) en agua intersticial, con el fin de determi-nar el efecto de la vegetación y de la inundación por la marea sobre los mismos. También se determinó la productividad pri-maria neta, tasa de descomposición y concentración de carbono, nitrógeno y fósforo en los tejidos aéreos y subterrá-neos y los pooles de estos elementos disponibles para el sistema, para ambas especies. En ambas marismas el pH varió en un rango estrecho (VM= 6,2 - 8,7 y PC= 7 - 8) y fue afectado por la presencia de vegetación pero no por la inundación. El Eh en VM varió entre -300 y 250 mV y fue influenciado por la marea, y por la vegetación sólo en zonas altas. En PC el Eh (rango= 50 250 mV) dependió de la inundación y de la vegetación. La concentración de MOP fue alta (VM ~5,5 mg/L y PC ~7,8 mg/L) y afectada sólo por la inundación en VM y sólo por la vegetación en PC. Tanto en VM como en PC, los nutrientes nitrogenados estuvieron en altas concentraciones, siendo generalmente el amonio la especie dominante, y tanto la vegetación como la inundación modificaron sus concentraciones. El fosfato y el silicato estuvieron siempre presentes en ambas áreas. El fosfato fue afectado sólo por la vegetación en VM, mientras que en PC sólo por la inundación. El silicato no se vió influenciado por ninguno de los dos factores considerados. La productividad total de S. alterniflora fue de 907 g p.s./m2.año, debida principalmente a tejidos subterráneos, y la de S. perennis de 1243 de g p.s./m2.año, correspondiendo mayormente a tejidos aéreos. En el caso de S. alterniflora, la productividad fue mayor en la marisma alta que en la baja. Las tasas de descomposición de tejidos aéreos y subterráneos de S. alterniflora fueron ~ 47 y ~ 29 % de material perdido luego de un año, respectivamente, mientras que para S. perennis fueron de ~ 64 y ~ 71 %, respectivamente.Los pooles de los elementos considerados fueron mayores para S. perennis que para S. alterniflora; en este ultimo caso, fueron mayores para marisma alta que para baja. Los resultados obtenidos mues-tran que existe un efecto de la vegetación así como de la inundación en los parámetros analizados. El efecto de la vegetación es mayor en marismas dominadas por S. perennis debido a los mayores pooles observados y sus mayores tasas de descomposición, en comparación con S. alterniflora. Por lo tanto, se puede concluir que las marismas del estuario de Bahía Blanca, especialmente las dominadas por S. perennis, efectivamente afectan los ciclos biogeoquímicos en el sistema. / Salt marshes are valuable ecosystems because, by occupying transition zones, play a central role in the exchange of organic matter, nutrients and pollutants between tidal flats and the adjacent waters. In this work, it is evaluated if the presence of halophytic species modify significantly the biogeochemical cycles of nutrients and organic matter in the Bahía Blanca estuary. The study was performed in two salt marshes, Villa del Mar (VM) and Puerto Cuatreros (PC), domi-nated by Spartina alterniflora and Sarcocornia perennis, respectively, the two most abundant halophytes in the system. pH and redox potential (Eh) in the sediments and the concentrations of dissolved nutrients and particulate organic matter (POM) in porewater were measured, in order to deter-mine the effect of vegetation and tidal flooding on them. In addition, net primary productivity, decomposition rate, con-centration of carbon, nitrogen and phosphorus in the above and belowground tissues and the pools of these elements available for the system were determined for both species. In both salt marshes pH varied in a narrow range (VM= 6.2 8.7 and PC= 7 - 8) and was affected by the presence of vegetation but not by flooding. Eh in VM varied between - 300 and 250 mV and it was influenced by the tide, and by vegetation only in high zones. In PC, Eh (range= 50 250 mV) depended on flooding and vegetation. The concentration of POM was high (VM ~5.5 mg/L and PC ~7.8 mg/L) and affected only by flooding in VM and only by vegetation in PC. In VM as well as in PC, nitrogen nutrients were present in high concentrations, being usually ammonium the dominant spe-cies, and vegetation and flooding modified their concentra-tions. Phosphate and silicate were always present in both areas. Phosphate was affected only by vegetation in VM, whereas in PC was only influenced by flooding. Silicate was affected by neither of the considered factors. The total pro-ductivity of S. alterniflora was of 907 g d.w./m2.yr, due mainly to belowground tissues, and that of S. perennis was of 1243 g d.w./m2.yr, which mostly corresponded to above-ground tissues. In the case of S. alterniflora, productivity was higher in the high marsh than in the low marsh. The decompo-sition rates of above and belowground tissues of S. alterni-flora were ~ 47 and ~ 29 % of lost material after a year, respectively, while for S. perennis they were of ~ 64 and ~ 71 %, respectively. The pools of the considered elements were higher for S. perennis than for S. alterniflora; in the latter case, they were higher for the high marsh than for the low marsh.The obtained results show that there is an effect of vegetation as well as flooding on the parameters analyzed. The effect of vegetation is greater in salt marshes dominated by S. perennis due to the higher pools found and the higher decomposition rates, compared with S. alterniflora. Hence, it is possible to conclude that salt marshes in the Bahia Blanca estuary, especially those dominated by S. perennis, affect the biogeochemical cycles in the system.

El Salitral de la Vidriera (Part. Villarino, Prov. Buenos Aires) presenta una gran cantidad de factores de estrés (sequía, salinidad, alta radiación, etc.) que impiden la implantación de muchas plantas; sin embargo, permite la existencia de otras que han logrado adaptarse a tales condiciones ambientales. El objetivo de esta tesis doctoral ha sido analizar la anatomía vegetativa de especies vegetales que conforman la comunidad xero-halófila que se desarrolla en dicho Salitral y la distribución espacial de las mismas en relación al gradiente de salinidad. A partir de esta relación se buscaron especies bioindicadoras que permitan estimar el grado de salinidad del suelo. Se ha estudiado la anatomía vegetativa (foliar y caulinar) de 35 especies pertenecientes a 15 familias botánicas. Hojas y tallos fueron tratados con técnicas tradicionales para estudios anatómicos y epidérmicos, así como también para la descripción de los macropatrones de cristales de oxalato de calcio. Se analizaron, además, muestras de la capa superficial del suelo a fin de cuantificar su salinidad. En gran parte de las especies estudiadas se identificaron características morfológicas y anatómicas que demuestran una alta adaptación al ambiente, siendo las hojas los órganos con mayor variedad de estas características. En general las adaptaciones están relacionadas con la reducción de la pérdida de agua por evapotranspiración y con los mecanismos de regulación de la concentración de sales. Entre las estrategias comunes pueden citarse: reducción del área foliar (por microfilia o plegamiento de las hojas), epidermis con células de paredes engrosadas, estomas pseudo-hundidos o protegidos por tricomas, tejido acuífero, etc. Particularmente en la organización del mesofilo se observaron diseños dorsiventrales, isolaterales y céntricos, siendo éste el carácter más variable entre los estudiados. En general en los tallos se encontraron caracteres que complementan los efectos de las variaciones anatómicas presentes en las hojas. Entre éstos pueden citarse: gran cantidad de tejidos de sostén mecánico (colénquima y esclerénquima) y rápido desarrollo de crecimiento secundario (típico o atípico). La distribución de las especies muestra una estrecha relación con las características del suelo. Ocho especies vegetales fueron consideradas como buenas bioindicadoras de salinidad debido a que su distribución espacial coincide con rangos estrechos de salinidad; con ellas se confeccionó una clave dicotómica que facilita su utilización como bioindicadores. Los estudios sobre especies vegetales de ambientes hostiles revisten especial importancia debido a los profundos cambios ambientales a los que se enfrenta el hombre; este conocimiento permitirá encontrar nuevas aplicaciones y/o utilidades para estas especies. / The Salitral de la Vidriera (Part. Villarino, Prov Buenos Aires) presents a lot of stress factors (drought, salinity, high radiation, etc.) that impede the implantation of many plants, allowing the existence of others which have successfully adapted to such environmental conditions. The objective of this thesis was to analyze the vegetative anatomy of plant species that form the xero-halophytic community of the mentioned salitral and the spatial distribution of these plants in relation with the salinity gradient. From this relationship, bioindicator species were sought to estimate the degree of soil salinity. The vegetative anatomy (leaf and stem) of 35 species belonging to 15 plant families were studied. Leaves and stems were treated with traditional techniques for anatomical and epidermal studies and also to describe their calcium oxalate crystals macropatterns. Samples of topsoil also were analyzed to quantify their salinity and then to find potential bioindicator species. In most of the studied species morphological and anatomical characteristics showed high adaptation to their environment, the leaves being the organs with the greatest variety of these characteristics. Adaptations are generally related to the reduction of water loss by evapotranspiration and mechanisms for regulation of salt concentration. The common strategies found include: reduction in leaf area (by microfily or folding of leaves), epidermal cells with thickened walls, pseudo-sunken stomata or protected by trichomes, aqueous tissue, etc. Particularly in the organization of the mesophyll were observed dorsiventral, isolateral and centric designs, this being the most variable character among those studied. In general stems characters complement the effects of anatomical variations present in the leaves. Among these may be mentioned: great development of mechanical supporting tissues (collenchyma and sclerenchyma) and rapid developing of secondary growth (typical or atypical). Relating the distribution of species with soil characteristics, it was observed that there is a relationship between them. Eight plant species were considered good salinity bioindicators, because their spatial distribution coincides with narrow ranges of salinity; they were compiled in a dichotomous key to simplify their use as bioindicators. Studies on plant species of hostile environments have particular importance due to profound environmental changes that men are facing to, this knowledge will contribute to find new applications and/or utilities for these species.

Foram realizadas análises isotópicas, físicas e químicas na água, no solo e nas plantas do Sistema de Produção Integrado Utilizando Efluentes de Dessalinização, criado pela Embrapa Semiárido, como uma alternativa para a reutilização desses efluentes na produção de alimentos e diminuição do impacto ambiental causado pelo descarte incorreto deste rejeito. O sistema avaliado se localiza no Campo Experimental da Caatinga, na Embrapa Semiárido (Petrolina-PE). Os resultados encontrados quanto à ciclagem dos nutrientes indicaram a ocorrência de uma contínua adição dos cátions Ca+2, Mg+2 , K+ e Na+ no solo durante o experimento, de 199 kg ha-1, 88 kg ha-1, 51 kg ha-1 e 142 kg ha-1, respectivamente. A eficiência de retirada do Ca+2, Mg+2 e Na+ pela Atriplex nummularia foi de 12,1, 4,3 e 23,9%, respectivamente; Ocorreu uma elevada perda de nitrogênio no sistema causado pelo processo de denitrificação, que diminuiu a concentração de nitrogênio em 72% do inicio ao final do sistema, levando este nutriente em quantidades insuficientes para a área agrícola. Estes resultados serão utilizados para indicar caminhos de melhorias no sistema. Ainda, quanto aos resultados isotópicos, foi possível concluir que: a água sofre um fracionamento durante o processo de osmose reversa na ordem de 1,87 para o 18O e 10,3 para o 2H; A água do poço é formada por uma mistura de águas recentes e paleoáguas; A relação 18O vs 2H; possui um coeficiente angular de 4,1, indicando elevada evaporação neste elemento; O solo avaliado possui uma média isotópica de -24 de 13C no solo de caatinga e -20 de 13C na área experimental, indicando uma troca da matéria orgânica desta área por material proveniente da Atriplex, que teve uma razão isotópica média de -13,7 .de 13C. / Isotopic, physical and chemical analysis were performed in water, soil and plants of the \" Integrated Production System Using Wastewater Desalination \", created Embrapa Semiarid, as an alternative to reuse of wastewater for food production and reducing the environmental impact caused by the incorrect disposal of the reject. The evaluated system is located in the Experimental Área Caatinga at Embrapa Semi-Arid (Petrolina-PE). The findings about the cycling of nutrients indicated the occurrence of a continuous addition of Ca+2, Mg+2, K+ and Na+ in the soil during the experiment of, 199 kg ha-1, 88 kg ha-1, 51 kg ha-1 and 142 kg ha-1, respectively. The efficiency of removal of Ca+2, Mg+2 and Na+ by Atriplex nummularia was 12,1, 4,3 and 23,9% respectively; Was observed high loss of nitrogen in the system caused by denitrification process, which decreased the concentration of nitrogen by 72% from beginning to end system, taking this nutrient in insufficient quantities to agricultural area. These results will be used for indicate ways to improve the system. Also, with the isotopic results was concluded that: water undergoes fractionation during the process of reverse osmosis the order of 1,87 to 18O and 10,3 for 2H; The well water is formed by a mixture of recent water and paleoáguas; The relationship 18O vs 2H; has a slope of 4,1, indicating high evaporation of this element; The soil has an average rated -24 in isotopic 13C in savanna soi and -20 of 13C in the experimental area, indicating an exchange of matter of this area of organic material from Atriplex, which had an average isotopic ratio of -13,7 . of 13C.

Submitted by Maria Beatriz Vieira (mbeatriz.vieira@gmail.com) on 2017-06-22T16:33:35Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) dissertacao_gabriele_espinel_avila.pdf: 937823 bytes, checksum: 425729d85c0200d3520fa3c39b5b7aae (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-06-22T20:38:09Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) dissertacao_gabriele_espinel_avila.pdf: 937823 bytes, checksum: 425729d85c0200d3520fa3c39b5b7aae (MD5) / Made available in DSpace on 2017-06-22T20:38:09Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) dissertacao_gabriele_espinel_avila.pdf: 937823 bytes, checksum: 425729d85c0200d3520fa3c39b5b7aae (MD5) Previous issue date: 2015-09-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Classificada como halófita facultativa, a quinoa (Chenopodium quinoa Willd.) é reconhecida por tolerar elevados níveis de salinidade. No Brasil, a cv. BRS Piabiru é a primeira recomendada para o cultivo granífero, constituindo alternativa para diversificação dos sistemas agrícolas. Contudo, estudos relativos à adaptação dessa cultivar no estado do Rio Grande do Sul, bem como às condições de salinidade ainda são necessários. Portanto, o objetivo deste trabalho foi avaliar as respostas fisiológicas (pigmentos e trocas gasosas) e bioquímicas (atividade enzimática antioxidante, teores de peróxido de hidrogênio, peroxidação lipídica, prolina e potencial osmótico) de plantas de quinoa cv. BRS Piabiru cultivadas sob condições de salinidade. O experimento foi conduzido em casa de vegetação onde as sementes foram distribuídas em vasos plásticos, preenchidos com areia lavada. Após sete dias da germinação foi fornecida solução nutritiva, ministrada a cada quatro dias e, aos 30 dias, foi realizado o desbaste, mantendo-se quatro plantas por vaso. Neste período também foram aplicadas as soluções salinas, na forma de cloreto de sódio, nas concentrações de 100, 200, 300 e 400 mM, além do tratamento controle cuja as plantas foram cultivadas na ausência da salinidade. As soluções nutritiva e salina foram aplicadas intercaladamente, a cada dois dias, até o fim do experimento. Aos 30, 60 e 90 dias após indução dos tratamentos, as plantas foram avaliadas quanto a parâmetros fisiológicos e bioquímicos (análises não destrutivas e destrutivas, respectivamente). Os dados foram submetidos à análise de variância (p≤0,05), as médias comparadas pelo teste de Tukey ao nível de 5% de probabilidade de erro e analisados por regressão polinomial. Houve redução no índice de clorofila e índice de balanço de nitrogênio e, a partir de 60 dias, incremento no índice de flavonoides. Neste período, a taxa de assimilação líquida de CO2 seguiu tendência quadrática de elevação até a concentração de 250 mM e as variáveis eficiência de uso da água e eficiência de carboxilação aumentaram linearmente com o incremento da salinidade. A atividade enzimática antioxidante, através das enzimas superóxido dismutase, catalase e ascorbato peroxidase, demonstrou que a salinidade promoveu adaptação e tentativa de neutralização das espécies reativas de oxigênio produzidas durante o estresse salino, tanto na parte aérea quanto em raízes. Houve aumento no potencial osmótico em ambos órgãos aos 90 dias após indução dos tratamentos, contudo, nas raízes a síntese de prolina não seguiu a mesma tendência. Apesar da redução nos índices de clorofila e de balanço de nitrogênio, há manutenção da taxa fotossintética, a qual, associada a capacidade antioxidante e ao ajuste osmótico até a concentração de 250 mM de NaCl, caracteriza a cv. BRS Piabiru com potencial de cultivo em solos sujeitos a salinização. / Classified as optional halophyte, quinoa (Chenopodium quinoa Willd.) is recognized for tolerate high levels of salinity. In Brazil, the cv. BRS Piabiru is the first recommended for grain production, providing an alternative for diversification of agricultural systems. However, studies on the adaptation of this variety in the state of Rio Grande do Sul, as well as the salinity conditions are still needed. Therefore, the objective of this study was to evaluate the physiological responses (pigments and gas exchange) and biochemical (antioxidant enzyme activity, hydrogen peroxide levels, lipid peroxidation, proline and osmotic potential) of quinoa plants cv. BRS Piabiru cultivated under saline conditions. The experiment was conducted in a greenhouse where the seeds were distributed in plastic pots filled with washed sand. After seven days of germination was supplied nutrient solution administered every four days and at day 30, the trimming was carried out, keeping four plants per pot. During this period the salt solutions have also been applied in the form of sodium chloride at concentrations of 100, 200, 300 and 400 mM, beyond which the control treatment plants were grown in the absence of salinity. The nutrient and saline solutions were applied interchangeably, every two days until the end of the experiment. At 30, 60 and 90 days after induction of treatments, the plants were evaluated for physiological and biochemical parameters (non-destructive and destructive analysis, respectively). Data were subjected to analysis of variance (p≤ 0.05), the averages compared by Tukey test at 5% error probability and analyzed by polynomial regression. There was reduction in chlorophyll content and nitrogen balance index and from 60 days, an increase in flavonoid content. During this period, net assimilation rate of CO2 followed quadratic upward trend until the concentration of 250 mM and the conditions of water use efficiency and carboxylation efficiency increased linearly with increasing salinity. The antioxidant enzyme activity by the enzyme superoxide dismutase, catalase and ascorbate peroxidase showed that the salinity promoted adaptation and attempt to neutralize the reactive oxygen species produced during salt stress, both in shoots and in roots. There was an increase of osmotic potential in both organs 90 days after induction of treatment, however, the roots proline synthesis did not follow the same trend. Despite the reduction in levels of chlorophyll and nitrogen balance, there is maintenance of photosynthetic rate, that, associated with antioxidant capacity and osmotic adjustment, until the concentration of 250 mM of NaCl, featuring the cv. BRS Piabiru with growing potential subjects soil salinization.

Foram realizadas análises isotópicas, físicas e químicas na água, no solo e nas plantas do Sistema de Produção Integrado Utilizando Efluentes de Dessalinização, criado pela Embrapa Semiárido, como uma alternativa para a reutilização desses efluentes na produção de alimentos e diminuição do impacto ambiental causado pelo descarte incorreto deste rejeito. O sistema avaliado se localiza no Campo Experimental da Caatinga, na Embrapa Semiárido (Petrolina-PE). Os resultados encontrados quanto à ciclagem dos nutrientes indicaram a ocorrência de uma contínua adição dos cátions Ca+2, Mg+2 , K+ e Na+ no solo durante o experimento, de 199 kg ha-1, 88 kg ha-1, 51 kg ha-1 e 142 kg ha-1, respectivamente. A eficiência de retirada do Ca+2, Mg+2 e Na+ pela Atriplex nummularia foi de 12,1, 4,3 e 23,9%, respectivamente; Ocorreu uma elevada perda de nitrogênio no sistema causado pelo processo de denitrificação, que diminuiu a concentração de nitrogênio em 72% do inicio ao final do sistema, levando este nutriente em quantidades insuficientes para a área agrícola. Estes resultados serão utilizados para indicar caminhos de melhorias no sistema. Ainda, quanto aos resultados isotópicos, foi possível concluir que: a água sofre um fracionamento durante o processo de osmose reversa na ordem de 1,87 para o 18O e 10,3 para o 2H; A água do poço é formada por uma mistura de águas recentes e paleoáguas; A relação 18O vs 2H; possui um coeficiente angular de 4,1, indicando elevada evaporação neste elemento; O solo avaliado possui uma média isotópica de -24 de 13C no solo de caatinga e -20 de 13C na área experimental, indicando uma troca da matéria orgânica desta área por material proveniente da Atriplex, que teve uma razão isotópica média de -13,7 .de 13C. / Isotopic, physical and chemical analysis were performed in water, soil and plants of the \" Integrated Production System Using Wastewater Desalination \", created Embrapa Semiarid, as an alternative to reuse of wastewater for food production and reducing the environmental impact caused by the incorrect disposal of the reject. The evaluated system is located in the Experimental Área Caatinga at Embrapa Semi-Arid (Petrolina-PE). The findings about the cycling of nutrients indicated the occurrence of a continuous addition of Ca+2, Mg+2, K+ and Na+ in the soil during the experiment of, 199 kg ha-1, 88 kg ha-1, 51 kg ha-1 and 142 kg ha-1, respectively. The efficiency of removal of Ca+2, Mg+2 and Na+ by Atriplex nummularia was 12,1, 4,3 and 23,9% respectively; Was observed high loss of nitrogen in the system caused by denitrification process, which decreased the concentration of nitrogen by 72% from beginning to end system, taking this nutrient in insufficient quantities to agricultural area. These results will be used for indicate ways to improve the system. Also, with the isotopic results was concluded that: water undergoes fractionation during the process of reverse osmosis the order of 1,87 to 18O and 10,3 for 2H; The well water is formed by a mixture of recent water and paleoáguas; The relationship 18O vs 2H; has a slope of 4,1, indicating high evaporation of this element; The soil has an average rated -24 in isotopic 13C in savanna soi and -20 of 13C in the experimental area, indicating an exchange of matter of this area of organic material from Atriplex, which had an average isotopic ratio of -13,7 . of 13C.