Using the short-lived radiotracer 13N, we examined the hypothesis that toxic, futile ammonia/ammonium (NH3/NH4+) fluxes at high external concentrations are mediated by ammonia-transporting aquaporins in roots of intact barley (Hordeum vulgare L.) plants. Effects of the aquaporin inhibitors zinc, copper, mercury, gold, silver, hydrogen peroxide, propionic acid, and nitrogen gas supported this hypothesis. Further tests with these inhibitors showed that changes in plant water potential and water content could be linked to NH3/NH4+ fluxes. An increase in external pH, causing an increase of NH3 in the nutrient solution, resulted in large increases of 13N influx, which can only be explained in energetic terms if the transported solute is neutrally charged. Taken together, the evidence here strongly supports the proposed hypothesis.

Using the short-lived radiotracer 13N, we examined the hypothesis that toxic, futile ammonia/ammonium (NH3/NH4+) fluxes at high external concentrations are mediated by ammonia-transporting aquaporins in roots of intact barley (Hordeum vulgare L.) plants. Effects of the aquaporin inhibitors zinc, copper, mercury, gold, silver, hydrogen peroxide, propionic acid, and nitrogen gas supported this hypothesis. Further tests with these inhibitors showed that changes in plant water potential and water content could be linked to NH3/NH4+ fluxes. An increase in external pH, causing an increase of NH3 in the nutrient solution, resulted in large increases of 13N influx, which can only be explained in energetic terms if the transported solute is neutrally charged. Taken together, the evidence here strongly supports the proposed hypothesis.

Equisetum giganteum L., a giant horsetail, is one of the largest living members of an ancient group of non-flowering plants with a history extending back 377 million years. Its hollow upright stems grow to over 5 m in height. Equisetum giganteum occupies a wide range of habitats in southern South America. Colonies of this horsetail occupy large areas of the Atacama river valleys, including those with sufficiently high groundwater salinity to significantly reduce floristic diversity. The purpose of this research was to study the ecophysiological and biomechanical properties that allow E. giganteum to successfully colonize a range of habitats, varying in salinity and exposure. Stem ecophysiological behavior was measured via steady state porometry (stomatal conductance), thermocouple psychrometry (water potential), chlorophyll fluorescence, and ion specific electrodes (xylem fluid solutes). Stem biomechanical properties were measured via a 3-point bending apparatus and cross sectional imaging. Equisetum giganteum stems exhibit mechanical characteristics of semi-self-supporting plants, requiring mutual support or support of other vegetation when they grow tall. The mean elastic moduli (4.3 Chile, 4.0 Argentina) of E. giganteum in South America is by far the largest measured in any living horsetail. Stomatal behavior of E. giganteum is consistent with that of typical C3 vascular plants, although absolute values of maximum late morning stomatal conductance are very low in comparison to typical plants from mesic habitats. The internode stomata exhibit strong light response. However, the environmental sensitivity of stomatal conductance appeared less in young developing stems, possibly due to higher cuticular conductance. Exclusion of sodium (Na) and preferential accumulation of potassium (K) at the root level appears to be the key mechanism of salinity tolerance in E. giganteum. Overall stomatal conductance and chlorophyll fluorescence were little affected by salinity, ranging from very low levels up to half strength seawater. This suggests a high degree of salinity stress tolerance. The capacity of E. giganteum to adapt to a wide variety of environments in southern South America has allowed it to thrive despite tremendous environmental changes during their long tenure on Earth.

Urban open spaces are of strategic importance to the quality of life of our increasingly urbanized society. Trees and related vegetation are planted and managed within the communities and cities to create or add value to the busy lives of the city dwellers. Trees in towns and cities form an important part of complex urban ecosystems and provide significant ecosystem services and benefits for urban dwellers, for example: reducing particulate pollution, carbon sequestration, decreasing air temperature, decreasing water runoff, aesthetic value and an increase in human health. Trees are solarpowered technology that can help restore balance to dysfunctional urban ecosystems. Trees form strands in the urban fabric that connect people to nature and to each other. The urban environment puts tremendous strain on trees by trenching, limited space for root growth and emission of pollutants into the atmosphere, water and soil. The problem is that the real impact of the urban environment on the trees within our community is unknown. The aim of this investigation was to assess the overall anthropogenic and environmental impacts on urban trees by measuring the tree vitality of Acacia karroo using chlorophyll fluorescence kinetics (JIP-test) and the leaf water potential using a pressure chamber. Tree vitality was quantified as the chlorophyll fluorescence-based performance index (PIABS)T. ree vitality measurements were also correlated with soil physical and chemical data. In the comparative study, an urbanization gradient approach was followed in which results of trees in rural areas were regarded as controls. The gradient approach is used worldwide and provides a background for questions of ecological structure and function. The urbanization gradient was quantified using the V-I-S model, based on % cover of vegetation, impervious surface and soil. Additionally, a model to determine the monetary value of trees in urban environments (SATAM) was tested. All this information could eventually contribute to develop an urban tree management program for Potchefstroom. It was evident from the current study that urbanization has a negative impact on tree vitality. The leaf water potential of a tree was, however, not necessarily negatively impacted upon. Although trees in urban environments did not always have a high vitality (PIABS)t, hey still played a major role in the urban environment. According to the tree appraisal method (SATAM), some of these trees have a value of R60 000. / Thesis (M. Environmental Science (Ecological Remediation and Sustainable Utilisation))--North-West University, Potchefstroom Campus, 2007.

O Brasil é destaque mundial na produção, na exportação e no consumo de café. Esta cultura ocupa cerca de dois milhões de hectares no território brasileiro, sendo plantada principalmente nos estados de MG, ES, SP e BA. A irrigação está presente em cerca de 10% da área plantada do cafeeiro arábica, já para o café robusta, este valor chega a 35%, o que torna o café uma das principais culturas irrigadas do Brasil. Porém, o déficit hídrico tornou-se o principal fator limitante da produção cafeeira, devido a expansão da cafeicultura para áreas consideradas marginais. A resposta do cafeeiro ao estresse hídrico pode ser avaliada utilizando-se medidas de potencial de água na folha no pré amanhecer, no entanto, essa metodologia restringe-se a atividades de pesquisa. O uso do CWSI (Crop Water Stress Index) calculado através da temperatura foliar como indicativo do potencial hídrico pode ser uma alternativa. O objetivo deste trabalho foi definir as relações entre o potencial de água na folha da cultura do café com o CWSI calculado através de medidas de temperatura com canhão infravermelho e com câmera térmica e analisar se estas relações apresentam bons índices de correlação, de precisão e de acurácia. O estudo foi realizado em um ambiente protegido localizado na área de pesquisa do Departamento de Engenharia de Biossistemas na Escola Superior de Agricultura \"Luiz de Queiroz\". A espécie plantada foi a Coffea arabica da variedade Catuaí Vermelho IAC 144, o sistema de irrigação adotado foi o gotejamento e o manejo foi feito por tensiometria. Utilizou-se o delineamento em blocos casualizados, sendo este formado por quatro blocos e quatro lâminas de irrigação (L130%, L100%, L70% e L40%) aplicadas em quatro épocas distintas (30/03 a 24/04, 07/06 a 02/07, 17/08 a 11/09 e 10/10 a 04/11) ao longo do ano de 2015. A unidade experimental foi representada por uma caixa com uma planta. Foram avaliadas a fração de radiação fotossinteticamente ativa interceptada, o potencial de água na folha e a temperatura foliar. A partir dos dados de temperatura foliar e dos dados meteorológicos calculouse o CWSI. As três variáveis avaliadas apresentaram relações significativas com os tratamentos impostos. O CWSI calculado para as diferentes situações e o potencial de água na folha apresentaram correlações bem representadas pelos modelos linear e cúbico. Os mesmos modelos apresentaram altos índices de precisão e acurácia. Conclui-se que o CWSI é um bom indicador do potencial hídrico da cultura do cafeeiro e pode substituir medidas do potencial de água na folha realizadas na câmara de Scholander. / Brazil is the world featured in production, export and consumption of coffee. This crop occupies about two million hectares in our country, it is mainly planted in state MG, ES, SP and BA. Irrigation is present in about 10% of the area planted arabica coffee, as for robusta coffee, this figure reaches 35%, which makes coffee one of the main irrigated crops in Brazil. But the drought has become the main limiting factor of coffee production due to the coffee growing expansion into areas considered marginal. The coffee response to water stress can be evaluated using water potential measurements on the sheet in the pre dawn, however, this methodology is limited to research activities. The use of CWSI (Crop Water Stress Index) calculated by leaf temperature as an indicator of water potential may be an alternative. The objective of this study was to define the relationship between the potential of water in the coffee culture of the sheet with the CWSI calculated from temperature measurements with infrared gun and thermal camera and analyze if these relations have good levels of correlation, accuracy and accuracy. The study was conducted in a protected environment located in the area of research in the Department of Biosystems Engineering at the School of Agriculture \"Luiz de Queiroz\". The planted species was the Coffea arabica variety Catuaí IAC 144, the adopted irrigation system was dripping and management was made by tensiometers. We used the randomized block design, which is made up of four blocks and four irrigation levels (L130%, L100%, L70% and L40%) applied in four different times (30/03 a 24/04, 07/06 a 02/07, 17/08 a 11/09 e 10/10 a 04/11) the 2015 year long. The unit experimental was represented by a box with a plant. We evaluated the intercepted photosynthetically active radiation fraction, water potential in the leaf and the leaf temperature. From the leaf temperature data and meteorological data we calculated the CWSI. The three variables evaluated showed significant relationships with tax treatments. The CWSI calculated for different situations and the potential of water in the sheet showed correlations well represented by linear and cubic models. The same models showed high precision and accuracy. It is concluded that the CWSI is a good indicator of water potential of the coffee crop and can replace water potential measurements on the sheet held in Scholander chamber.

Thesis (M. Environmental Science (Ecological Remediation and Sustainable Utilisation))--North-West University, Potchefstroom Campus, 2007.

Urban open spaces are of strategic importance to the quality of life of our increasingly urbanized society. Trees and related vegetation are planted and managed within the communities and cities to create or add value to the busy lives of the city dwellers. Trees in towns and cities form an important part of complex urban ecosystems and provide significant ecosystem services and benefits for urban dwellers, for example: reducing particulate pollution, carbon sequestration, decreasing air temperature, decreasing water runoff, aesthetic value and an increase in human health. Trees are solarpowered technology that can help restore balance to dysfunctional urban ecosystems. Trees form strands in the urban fabric that connect people to nature and to each other. The urban environment puts tremendous strain on trees by trenching, limited space for root growth and emission of pollutants into the atmosphere, water and soil. The problem is that the real impact of the urban environment on the trees within our community is unknown. The aim of this investigation was to assess the overall anthropogenic and environmental impacts on urban trees by measuring the tree vitality of Acacia karroo using chlorophyll fluorescence kinetics (JIP-test) and the leaf water potential using a pressure chamber. Tree vitality was quantified as the chlorophyll fluorescence-based performance index (PIABS)T. ree vitality measurements were also correlated with soil physical and chemical data. In the comparative study, an urbanization gradient approach was followed in which results of trees in rural areas were regarded as controls. The gradient approach is used worldwide and provides a background for questions of ecological structure and function. The urbanization gradient was quantified using the V-I-S model, based on % cover of vegetation, impervious surface and soil. Additionally, a model to determine the monetary value of trees in urban environments (SATAM) was tested. All this information could eventually contribute to develop an urban tree management program for Potchefstroom. It was evident from the current study that urbanization has a negative impact on tree vitality. The leaf water potential of a tree was, however, not necessarily negatively impacted upon. Although trees in urban environments did not always have a high vitality (PIABS)t, hey still played a major role in the urban environment. According to the tree appraisal method (SATAM), some of these trees have a value of R60 000. / Thesis (M. Environmental Science (Ecological Remediation and Sustainable Utilisation))--North-West University, Potchefstroom Campus, 2007.

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 6 uppsatser.

The application of potassium (K) and lime as a source of Calcium (Ca) and Magnesium (Mg) in soil may affect the growth and nutritional status of young plants of grapevines as well as grape production, must composition and distribution of forms of K in the soil. This study aimed to i) evaluate the growth and nutritional status of young grapevines submitted to the application of K lime in soil ii) evaluate how potassium fertilization affects the grape production, must composition and alterations of forms of K in soil, and iii) evaluate the potential of water in leaves as well as the nutritional status and must composition of grapevines grown with or without irrigation. Four studies were carried out. In study I, two experiments were performed in Campanha Gaucha (RS) in order to assess young plants. In the experiment 1, 0, 30 and 60 kg K2O ha-1were applied. In the experiment 2, 0, 60, 120, and 180 kg K2O ha-1were applied with application of dolomitic and calcitic lime. The K content in leaves, plant height, stem diameter and pruned material weight were evaluated. Studies II, III and IV were carried out for plants in production with the installation of three other experiments. One of the experiments was performed in Serra Catarinense (SC) with 0, 50, 100, 150 and 200 kg K2O ha-1 yr-1. The second experiment was in Campanha Gaucha with five levels of K in the soil. The K content in leaf, berries, grape yield components, and must composition were evaluated in both experiments. The third experiment was carried out in the region of Trento (Italy) with grapevines in production, with or without irrigation the soil, where the water potential of plants as well as the nutrient content in the leaf and berry of grapes were evaluated. In the experiment with young plants, soil potassium fertilization increased the K only in the 0-10 cm layer and influenced the content of K in the leaves in the first season; however, it did not influence the growth of cv. Chardonnay or Pinot Noir. For plants in production in Serra Catarinense there was an increase in the levels of exchangeable, non-exchangeable and total K in soil with the application of potassium fertilizer. The application of K in the soil increased the concentration of K in leaf and petioles of grapevines; however, it did not affect grape production or the must composition. In Campanha Gaucha, the increase of the content of exchangeable K in the soil increased the total K in the leaves in flowering, the K content in the berries and the pH of the must; however, it did not affect grape production. Although providing less negative water potential in grapevine leaves, irrigation did not affect nutritional status or the enological parameters of the berry, showing little interference in its nutrient content. / A aplicação de potássio (K) e calcário, como fonte de Ca e Mg no solo, podem afetar o crescimento e o estado nutricional de plantas jovens de videiras, assim como, pode afetar a produção de uva, composição do mosto e alterar a distribuição das formas de K no solo. O trabalho objetivou (a) avaliar o crescimento e o estado nutricional de videiras jovens submetidas à aplicação de K calcários no solo (b) avaliar como a adubação potássica pode afetar a produção de uva, composição do mosto e alteração das formas de K no solo (c) avaliar o potencial de água em folhas, o estado nutricional e a composição do mosto, de videiras cultivadas com e sem irrigação. Foram realizados quatro estudos. Para avaliar plantas jovens, no estudo I, foram instalados dois experimentos na Campanha Gaucha (RS), onde foi aplicado, no experimento 1: 0,30 e 60 kg de K2O ha-1; e no experimento 2: 0, 60, 120, e 180 kg de K2O ha-1, com aplicação de calcário calcítico e dolomítico. Avaliou-se o teor de K em folhas, a altura de plantas, diâmetro de caule e massa do material podado. Para plantas em produção, Estudos II, III e IV, foram instalados outros três experimentos. Na Serra Catarinense (SC) com 0, 50, 100, 150 e 200 kg de K2O ha-1 ano-1 e outro na Campanha Gaucha com 5 níveis de K no solo, em ambos foram avaliados os teroes de K na folha, nas bagas, componentes de rendimento da uva e composição do mosto. Na região de Trento (Itália) foi instalado um experimento com videiras em produção, com e sem irrigação do solo, onde foi avaliado o potencial hídrico das plantas, além do teor de nutrientes na folha e na baga de uva. No experimento com plantas jovens, a adubação potássica no solo incrementou os teores de K somente na camada de 0-10 cm, influenciou o teor de K nas folhas na primeira safra, porém não influenciou os parâmetros de crescimento nas cv. Chardonnay e Pinot Noir. Para plantas em produção na Serra Catarinense houve incremento nos teores de K trocável, não trocável e total no solo com a aplicação da adubação potássica. A aplicação de K no solo aumentou os teores de K no limbo e pecíolo das videiras, mas não afetou a produção de uva e a composição do mosto. Na Campanha o incremento do teor de K trocável no solo aumentou o K total nas folhas no pleno florescimento, o teor de K nas bagas e o valor de pH do mosto, mas não afetou a produção de uva. A irrigação, apesar de proporcionar potencial de água menos negativo nas folhas da videira, não afetou o estado nutricional, os parâmetros enológicos e pouco interferiu no teor de nutrientes na baga.

Submitted by DANIEL DOS SANTOS VIAIS NETO null (dvneto@gmail.com) on 2016-06-17T14:42:35Z No. of bitstreams: 1 TESE - Daniel dos Santos Viais Neto.pdf: 1994747 bytes, checksum: af65171f111a7da468c3f93b43c93b28 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-06-21T19:17:36Z (GMT) No. of bitstreams: 1 viaisneto_ds_dr_bot.pdf: 1994747 bytes, checksum: af65171f111a7da468c3f93b43c93b28 (MD5) / Made available in DSpace on 2016-06-21T19:17:37Z (GMT). No. of bitstreams: 1 viaisneto_ds_dr_bot.pdf: 1994747 bytes, checksum: af65171f111a7da468c3f93b43c93b28 (MD5) Previous issue date: 2016-05-23 / O tomate, a mais popular das hortaliças, caracteriza-se por ser uma cultura exigente em água e, quando em déficit hídrico prolongado e severo, tem limitações em seu crescimento e redução em sua produtividade. Além disto, esta hortaliça é afetada pelo excesso de salinidade na água, que ocasiona murchamento foliar, queimadura do ápice e das bordas da folha e até sua morte. Tais efeitos, em geral, são analisados utilizando técnicas estatísticas, mas existem teorias matemáticas que permitem ajustes mais refinados, destacando-se dentre elas, a lógica fuzzy. O objetivo deste trabalho foi avaliar o desenvolvimento e a produtividade do tomate híbrido em diferentes tensões de água no solo e diferentes doses de salinidade na irrigação ao longo de seu ciclo utilizando modelagem fuzzy. Esta avaliação foi desenvolvida em dois capítulos, sendo o primeiro sobre a análise dos efeitos da irrigação e da salinidade da água no ponto de colheita desta cultura; enquanto que o segundo se trata dos efeitos da irrigação e da salinidade da água nos parâmetros de desenvolvimento em diferentes estádios da cultura. Utilizou-se dados de um experimento que foi realizado em um ambiente protegido situado na área experimental na Faculdade de Ciências Agronômicas - FCA/UNESP, Campus de Botucatu - SP. As variáveis de entrada dos sistemas fuzzy foram Irrigação, Salinidade e DAS, enquanto que as de saída elegeu-se as variáveis das análises biométricas e de produtividade que apresentaram diferenças estatísticas significativas. As análises dos efeitos da irrigação e salinidade foram realizadas por meio de gráficos tridimensionais e mapas de contorno das variáveis de saída. Foi possível inferir pelos modelos elaborados que as variáveis de desenvolvimento e de produtividade apresentaram resultados satisfatórios quando se utilizou irrigação em capacidade de campo e/ou salinidade nula. Além disso, as modelagens desenvolvidas neste trabalho podem ser adaptadas e utilizadas para avaliar outras culturas. / Tomato, the most popular of vegetables, is characterized by being a water-demanding crop and, when in prolonged and severe drought, presents growth limitations and reduction in productivity. In addition, this vegetable is affected by excess of water salinity, which causes leaf wilting, leaf apex and edges burn and even its death. These effects are usually analyzed using statistical techniques, but there are mathematical theories that allow finer adjustments, among which, fuzzy logic is highlighted. The objective of the present study was to evaluate the development and productivity of hybrid tomato in different water tensions in soil and different doses of salinity in irrigation throughout its cycle using fuzzy modeling. The evaluation was conducted in two chapters, the first one on the analysis of the effects of irrigation and water salinity at the harvest point of the crop; while the second one deals with the effects of irrigation and water salinity in development parameters at different stages of the culture. Data from an experiment conducted in a greenhouse located at the experimental area at the Faculdade de Ciências Agronômicas - FCA/UNESP in Botucatu - SP campus were used. The input variables of fuzzy systems were Irrigation, Salinity and DAS, while the output ones were the biometric and productivity analysis variables that showed statistically significant differences. Analyses of the effects of irrigation and salinity were performed through three-dimensional graphics and through output variables outline maps. It can be inferred through the elaborated models that the development and productivity variables showed satisfactory results when field capacity irrigation and/or zero salinity were used. Moreover, the modeling developed in the present work can be adapted and used to evaluate other crops.