Julierme Zimmer Barbosa

Zinc, copper and manganese availability in soils treated with alkaline sewage sludge from Paraná state (Brazil)

No Parana, a maioria do lodo de esgoto gerado em estacoes de tratamento e submetida ao processo de estabilizacao alcalina prolongada. Embora seja conhecido que o lodo de esgoto alcalinizado contem micronutrientes como Zn, Cu e Mn, pouco se conhece sobre a disponibilidade desses elementos em solos tratados com esse tipo de lodo de esgoto. Assim, o objetivo do estudo foi avaliar a influencia de lodos de esgoto alcalinizados do estado do Parana sobre a disponibilidade de Zn, Cu e Mn no solo. Foram selecionadas vinte estacoes de tratamento de esgoto ao longo do Parana, onde foram coletadas amostras de lodo de esgoto alcalinizado e amostras do solo agricola mais representativo da regiao. Cada solo foi incubado por 60 dias com doses de lodo de esgoto (0, 10, 20, 40, e 80 Mg ha-1) da sua regiao. Posteriormente, foi determinada a disponibilidade de Zn, Cu e Mn no solo usando o extrator Mehlich-1. A aplicacao de lodo de esgoto alcalinizado ao solo aumentou a disponibilidade de Zn e diminuiu a disponibilidade de Mn na maioria dos solos. Ja o Cu apresentou resultados intermediarios, com aumento de disponibilidade basicamente em solos de textura media e com diminuicao para a maioria dos solos muito argilosos. Em solos com pH proximo ao ideal para o cultivo agricola, a dose de lodo de esgoto alcalinizado deve ser cuidadosamente calculada para que nao ocorra o aumento excessivo do pH e desbalanco nos teores de Zn, Cu e Mn.

SOIL FERTILITY AFFECTS ELEMENTAL DISTRIBUTION IN NEEDLES OF THE CONIFER Araucaria angustifolia: A MICROANALYTICAL STUDY

Araucaria angustifolia is a conifer species found in South American subtropical forests that comprises less than 3% of the native vegetation and little is known concerning the accumulation of nutritional elements in its needles. In this study, scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) was used to assess the elemental distribution in needles. Needles were selected from 28 month-old plants grown in a fertilization experiment supplied with: 1) N, P, and K; 2) N and P; and 3) N and K. In microanalysis, four types of specialized needle tissues (adaxial epidermis, palisade mesophyll, spongy mesophyll and abaxial epidermis) were evaluated for elemental composition (C, O, P, K, Ca, S and Al). When crystals were detected, the concentrations of 12 elements were determined (C, O, P, K, Ca, S, Al, Fe, Mg, Na, Si, and Cl). Under low soil P and K, these elements were found in low concentrations in the epidermis, mesophyll, and crystals. Under low soil P, Ca and K accumulated in the spongy mesophyll, while under low soil K only Ca accumulated in this tissue. In addition, low soil P or K availability favored the formation of crystals; crystals under low soil K availability had more Ca and Mg. Soil P and K availability affected the distribution of elements in needles of A. angustifolia, in that type of tissue and formation of crystals were key to the nutrient dynamics in needles. FERTILIDADE DO SOLO AFETA A DISTRIBUIÇÃO DE ELEMENTOS EM ACÍCULAS DA CONÍFERA Araucaria angustifolia: UM ESTUDO MICROANALÍTICO RESUMO: Espécie da floresta subtropical da América do Sul e restando apenas menos de 3 % de vegetação natural, a Araucaria angustifolia é ainda pouco conhecida sobre a distribuição de elementos em suas acículas. Nesse estudo, utilizamos microscopia eletrônica de varredura (MEV) com espectroscopia por dispersão de energia (EDS) para avaliar a distribuição elementar em acículas de A. angustifolia. Foram selecionadas acículas de plantas (28 meses de idade) cultivadas em experimento de adubação: com suprimento de N, P e K; com N e P; com N e K. Na microanálise quatro tipos de tecidos especializados das acículas (epiderme superior, mesófilo paliçádico, mesófilo esponjoso e epiderme inferior) foram avaliados quanto a composição (C, O, P, K, Ca, S e Al). Quando foram detectados cristais determinaram-se as concentrações de 12 elementos (C, O, P, K, Ca, S, Al, Fe, Mg, Na, Si e Cl). Na baixa disponibilidade de P e K, esses elementos foram encontrados em baixas concentrações na epiderme, no mesófilo e em cristais. Na baixa disponibilidade de P ocorreu acúmulo de Ca e K no mesófilo esponjoso, enquanto que na baixa disponibilidade de K ocorreu acúmulo de Ca no mesófilo esponjoso. Em adição, a baixa disponibilidade de K e P favoreceu a formação de cristais, sendo que em baixa disponibilidade de K, os cristais apresentaram mais Ca e Mg. A disponibilidade de P e K no solo afetou a distribuição de elementos em acículas de A. angustifolia, sendo que o tipo de tecido e a formação de cristais foi chave para a dinâmica de nutrientes nas acículas.

COMPOSITION, HOT-WATER SOLUBILITY OF ELEMENTS AND NUTRITIONAL VALUE OF FRUITS AND

Yerba mate leaves are the most studied and used parts of the tree, while fruits have been little investigated as to their elemental composition. The objective of this study was to characterize the composition, the hot-water solubility of the elements and the nutritional value of yerba mate (Ilex paraguariensis St. Hill) fruits and leaves. Both fruits and leaves were collected from four yerba mate provenances (cities of Cascavel, Quedas do Iguacu and Ivai in Parana state and Barao de Cotegipe in Rio Grande do Sul state) 17 years of age, grown in the city of Pinhais, Parana state, Brazil. The total and hot water-soluble contents of 22 and 20 elements, respectively, were determined. The elemental composition of the fruits presented the following decreasing order: C, K, N, Mg, Ca, P, Al, Na, Zn, Mn, Fe, Ba, Cu, Ni, Mo, Pb, Cr, As, Co, Ag, V and Cd. For the leaves the decreasing order was: C, N, K, Ca, Mg, P, Al, Mn, Na, Fe, Zn, Ba, Cu, Ni, Pb, Cr, Mo, As, Co, Ag, V and Cd. It was found than 2 to 8 elements in the fruit presented greater water solubility than in the leaves. In case of consumption via infusion of the fruits or leaves, there would be nutritive value for K, Mg, P, Mn, Cr, Mo, Cu and Zn, while consumption of capsules would have nutritive value only for Mn via the leaves. In general, the fruits have more distinct elemental composition, hot-water solubility and nutritional value than yerba mate leaves.

Uso de imagens digitais obtidas com câmeras para analisar plantas

Analises visuais de plantas sao realizadas pelo homem de forma empirica desde os primordios da agricultura. Atualmente, com o advento de câmeras digitais (RGB, multiespectro, hiperespectro e termicas) o uso de imagens ganha impulso como instrumento de avaliacao de plantas. A utilizacao de câmeras digitais para analise de plantas e um metodo nao destrutivo, rapido e reprodutivel, com a possibilidade de armazenamento das imagens em bancos de dados para avaliacoes futuras. Diagnoses visuais de imagens podem apresentar reduzidas possibilidades de extracao de informacoes, assim, torna-se importante a utilizacao de programas para analisar questoes de interesse em uma imagem. Quando nao ha um programa especifico para a analise de determinada imagem e necessaria maior manipulacao, geralmente envolvendo transformacao de formato, edicao, analise em programas comuns e digitacao de dados, assim, a utilizacao de programas especificos se faz necessaria para facilitar o processo de aquisicao e analise dos dados. A analise de plantas atraves de imagens tem sido realizada em todos os orgaos vegetais, em escalas que variam de micro ate macroscopica e em ambientes diversificados. Desse modo, esta revisao de literatura visa buscar o estado da ciencia da analise de plantas por imagens digitais.

Depicting the physiological and ultrastructural responses of soybean plants to Al stress conditions

Aluminium (Al) is a toxic element for plants living in soils with acidic pH values, and it causes reductions in the roots and shoots development. High Al concentrations can cause physiological and structural changes, leading to symptoms of toxicity in plant tissue. The aim of this study was to describe the Al toxicity in soybean plants through physiological, nutritional, and ultrastructure analyses. Plants were grown in nutrient solution containing increasing Al concentrations (0; 0.05; 0.1; 1.0, 2.0 and 4.0 mmol L-1). The Al toxicity in the soybean plants was characterized by nutritional, anatomical, physiological, and biochemical analyses. The carbon dioxide assimilation rates and stomatal conductance were not affected by the Al. However, the capacity for internal carbon use decreased, and the transpiration rate increased, resulting in increased root biomass at the lowest Al concentration in the nutrient solution. The soybean plants exposed to the highest Al concentration exhibited lower root and shoot biomass. The nitrate reductase and urease activities decreased with the increasing Al concentration, indicating that nitrogen metabolism was halted. The superoxide dismutase and peroxidase activities increased with the increasing Al availability in the nutrient solution, and they were higher in the roots, showing their role in Al detoxification. Despite presenting external lesions characterized by a damaged root cap, the root xylem and phloem diameters were not affected by the Al. However, the leaf xylem diameter showed ultrastructural alterations under higher Al concentrations in nutrient solution. These results have contributed to our understanding of several physiological, biochemical and histological mechanisms of Al toxicity in soybean plants.

Clay mineralogy affects the efficiency of sewage sludge in reducing lead retention of soils

Recent studies have shown the feasibility of using of sewage sludge for the remediation of heavy metal-contaminated soils. However, there are no researches to check the influence of clay mineralogy on the efficiency of the sewage sludge to remediation of contaminated soils with heavy metals. For this purpose, we use two contrasting soils: Oxisol rich in hematite and gibbsite and Inceptisol rich in kaolinite. Thermal-treated sludge was applied to Pb-contaminated soil samples and incubated for 40 days. The soil samples were submitted to seven sequential extractions: soluble-Pb, exchangeable-Pb, precipitated-Pb, organic matter-Pb, Fe and Mn oxide-Pb, gibbsite and kaolinite-Pb, and residual-Pb. The reduction of soluble Pb forms by thermal sludge application was more pronounced in the Oxisol than in the Inceptisol because of the conversion of soluble-Pb into more stable forms, such as precipitated-Pb and oxides-Pb. For Inceptisol was necessary to apply high rates of thermal sludge to reach a significant reduction in soluble-Pb contents. The addition of humic fractions in the form of thermal sludge increased the concentration of organic matter-Pb. In confined area, the use of sewage sludge to reduce the heavy metals levels in soils must be better considered, mainly in more weathered soils.

Plant growth, nutrients and potentially toxic elements in leaves of yerba mate clones in response to phosphorus in acid soils.

Native to subtropical region of South America, yerba mate is responsive to P under some conditions, but the degree of influence of genetic and soil on the growth and composition of the leaf is unknown. The aim of study was to evaluate plant growth, nutrients and potentially toxic elements in leaves of yerba mate clones in response to P application in acid soils. In greenhouse condition, two yerba mate clone seedlings were grown (210 days) in pots, each clone in a completely randomized design in factorial scheme (with and without P; four acid soils). The elemental composition of leaves and the growth of plants were determined. Phosphorus promoted plant growth, but this was not accompanied by increased P in leaf tissue in all conditions tested. The P effect on the elemental composition varied: decrease/null (N, K, Mg, Mn, Cu, Ni, B, Mo, Al, Cd); increase/null (C/N, C, Ca, Fe, V); increase/decrease/null (Zn, Ba, Pb) and; null (Cr). The soils affect the elemental composition of the leaves, especially Mn, with accumulation greater than 1000 mg kg-1. The Ba, Pb, Al and Zn in the leaves varied among clones. Yerba mate response to P was affected by edaphic and plant factors.

Production, carbon and nitrogen in stover fractions of corn ( Zea mays L.) in response to cultivar development

A alteracao na quantidade e qualidade dos residuos culturais do milho podem impactar a conservacao do solo e o sequestro de C no solo para extensas areas. O objetivo do estudo foi avaliar as alteracoes na producao, concentracao e quantidade de C e N nas fracoes do residuo do milho em resposta ao desenvolvimento do cultivar. Foram conduzidos dois experimentos de campo na cidade de Rolândia (estado do Parana, Brasil), sendo cultivados dez cultivares representantes dos cinco niveis tecnologicos que seguem: hibridos de cruzamento simples, duplo ou triplo, variedades comerciais e cultivares crioulas. No final do ciclo foi determinada a altura das plantas e o peso de colmos, folhas, sabugos, bracteas e pendao. Foi realizada a analise elementar em triplicata para C e N em cada fracao do residuo. Em geral, cultivares crioulas tiveram maior altura de planta e materia seca (kg ha-1) e conteudo de C (kg ha-1) nas bracteas, folhas, pendoes e colmo, principalmente em comparacao aos hibridos simples ou outros hibridos. Ocorreu relacao direta entre a relacao C/N e a selecao do milho para bracteas para ambos os experimentos e para outras fracoes no primeiro experimento. Esse resultado foi devido ao aumento do C e reducao do N pela selecao da cultura. Foi observada diferenca dentro do mesmo nivel tecnologico para as variaveis analisadas, sugerindo ampla variacao de linhagem genotipica. A quantidade e a qualidade das fracoes do residuo variaram entre cultivares de milho e pode afetar o seu uso como cobertura de solo, alimentacao de animais, energia e outros.