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The influence of temperature and rainfall on nutrient levels, heavy metals, and etiologic agents in sludge samples collected at the Sewage Treatment Station of Juiz de Fora, Minas Gerais, Brazil, was verified over 24 months. The results showed high levels of nitrogen (4.7-5.2%), phosphorus (1.4-2.2%), potassium (0.076-0.106%), magnesium (0.113-0.386%), iron 5.03%) and zinc (38.2-6902.1 mg Kg-1). For most of the investigated samples, the concentration of zinc was above the maximum allowed value (2,800 mg Kg-1). The concentrations of arsenic, cadmium, chrome, copper, and lead were below the maximum values allowed by the legislation. Parasitological analyzes identified thermotolerant coliforms (0.49-160 NMP g-1) and helminth eggs (1 egg), however, in amounts less than allowed by legislation. These results are indicative of the efficiency of the sewage treatment process. The results showed a significant influence of the meteorological parameters on the concentrations of nitrogen, copper, lead, zinc and pathogens in the sludge. The results also showed a strong correlation between the concentrations of copper, lead and zinc indicating that the presence of these elements in the sewage sludge has a common origin. The results demonstrated the feasibility of using the investigated matrix as fertilizer when collected in rainy periods when it favors the dilution of the elements present in their soluble forms.

Lippia alba (Mill.) NE Br. ex Britton & P. Wilson is an important medicinal herb widely distributed in Latin America. However, the success of this crop depends on several biotic and abiotic environmental factors, being water availability the most limiting one. Therefore, the present paper aimed to investigate the responses of one tetraploid (tet) and two diploids (dip1 and dip2) genotypes of L. alba to drought stress by using irrigation suspension under 0 (control) or 15 (stressful factor) days. The physiological parameters water content, gas exchange, chlorophyll a fluorescence, photosynthetic pigments contents, and the qualitative profile of volatile organic compounds were evaluated by uni- and multivariate statistical analyses. Drought stress negatively affected the physiological processes in all L. alba specimens equally, regardless of the genotype. It was observed that photosynthesis was impaired due to stomatal limitation, which was triggered by low water availability. In contrast, the qualitative profile of volatile organic compounds was strongly determined by genotype without drought stress influence. Furthermore, gas exchange and chlorophyll a fluorescence were the most sensitive parameters to evaluate drought stress in L. alba. More specifically stomatal conductance is recommended to be evaluated in L. alba breeding programs focused on drought stress tolerance, given that its high contribution to photosynthesis regulation.

Zinc and lead are trace elements of major environmental concern, as they can originate from point and non-point polution sources and bioacumulate in food webs, with potential risk to human health. Steel industries produce large amounts of residues that may contain Zn and Pb, and the effect of disposing these materials in the environment is little studied in Brazil. This work aimed to select different chemical extractants (water, Mehlich-1, diethylene triamine pentacetic acid - DPTA, citric acid, and concentrated nitric acid) to estimate Zn and Pb availability to elephant grass and common beans. Three different residues (steel slag, filter-press mud and phosphate mud) in five doses (0, 1, 2, 4 and 8 Mg ha-1) were added to a Latosol. Water-soluble Zn comprised a significant part of the total, suggesting its higher solubility and potential contamination of soil, water and plant, when compared to Pb. Pearson correlation coefficients between Zn in plant and soil, for all extractors, were generally higher than for Pb. The correlation coefficients of Zn and Pb levels in soils and plant tissues varied with time and extractor, and DPTA was the most adequate for both elements.

Introduction Aluminum toxicity is commonly verified in acidic soils, and poses a severe limitation to plant growth and development. Therefore, Al complexation by the root system mucilage, Al complexation by organic compounds that are exuded by the roots and internal metabolic processes must be monitored by organic acids (OA), since they play a central role in these aluminum tolerance mechanisms. Objective To optimise a capillary zone electrophoresis method able to perform simultaneous separation of acetic, citric, formic, lactic, malic, oxalic, pyruvic, succinic, tartaric and aspartic acid in plant extract solutions. Methodology Method optimisation was achieved by a chemometric approach through experimental designs. The optimal condition found was: 20 mmol/L phthalic acid buffer; 0.8 mmol/L cetyltrimethyl-ammonium bromide; pH 3.4 adjusted with tris(hydroxymethyl)aminomethane (around 16 mmol/L); −15 kV of voltage; 25 °C of cartridge temperature; indirect ultraviolet detection at 240 nm; and 25 mbar injection for 2 s, within an analysis time of 4 min. Results As a repeatability test of the optimal condition, 30 replicates were carried out with the same working electrolyte, where the relative standard deviation of each peak ranged from 0.081 to 0.36% (for migration time) and from 2.4 to 4.6% (for peak area). Conclusion The methodology was successfully applied to simultaneously determine citric, malic and aspartic acid in roots and leaves extract solutions of Brachiaria brizantha, demonstrating its usefulness to study aluminum tolerance. Copyright © 2012 John Wiley & Sons, Ltd.

A study was carried out to evaluate the development of 12 tetraploid alfalfa cultivars exposed to Al toxicity in nutrient solution. Newly germinated seedlings of cultivars Alfa 200, Alto, Araucana, Costera, Crioula, Esmeralda, Falcon, F-708, Rio, Romagnola, Valley Plus, and Victoria, were exposed to either 0, 4, 8 or 12 mg·L-1 Al3+. Plants were analyzed regarding root length (RL) and dry matter (RDM), aerial part length (APL), and dry matter (APDM), hypocotyl length (HypL) and dry matter (HypDM), epicotyl length (EpiL) and dry matter (EpiDM), and petiole length (PetL), and dry matter (PetDM). Results indicated that, although all genotypes exhibited detectable sensitivity to such a stress, cvs. Crioula, Victoria and Alpha-200 were tolerant to 4 mg·L-1 Al3+ toxicity. It was also concluded that Al3+ levels up to the 4 mg·L-1 will be effective for screening tetraploid alfalfa genotypes regarding this type of stress, when evaluations are made in nutrient solution. Finally, RL is the most suitable variable for conducting such evaluations, but all variables related to dry matter in the aerial part are also recommended.

Objetivou-se, com este estudo, avaliar a mobilidade de Pb e Zn no solo. Instalou-se um experimento, em casa-de-vegetação, em vasos preenchidos com amostras de Latossolo Vermelho-Amarelo, submetidas a doses de resíduos siderúrgicos, sob delineamento inteiramente casualizado, em esquema fatorial 3×5, com três repetições, combinando-se três resíduos siderúrgicos (carepa de aciaria, lama de filtro-prensa e lama de fosfato), com cinco doses de cada resíduo (0 t ha-1, 1 t ha-1, 2 t ha-1, 4 t ha-1 e 8 t ha-1). Cultivou-se capim-elefante, por 120 dias, e, posteriormente, realizou-se o cultivo de feijão, durante 75 dias. Neste período, avaliaram-se as concentrações de Pb e Zn no lixiviado. Não houve lixiviação de Pb, porém, o Zn apresentou bastante mobilidade na coluna de solo. Em solo adubado com carepa de aciaria e lama de filtro-prensa, não foram observados riscos de contaminação do lençol freático por Zn e Pb, entretanto, a dose de 8 t ha-1 de lama de fosfato elevou os teores de Zn no lixiviado acima do máximo permitido pela legislação. Tal fato limita o uso deste último resíduo em doses altas. Os demais resíduos (carepa de aciaria e lama de filtro-prensa) devem ser testados em experimentos de campo, visando à sua possível utilização agrícola. In order to evaluate the dynamics of Zn and Pb in the soil, a greenhouse experiment was set up in pots filled with soil samples (Typic Hapludox) treated with increasing doses of iron smelting residues. It was set under a completely randomized design, in a 3×5 factorial scheme, with three replications, combining three iron smelting residues (mill scale, filter press mud, and phosphate mud), with five doses for each residue (0 t ha-1, 1 t ha-1, 2 t ha-1, 4 t ha-1, and 8 t ha-1). Elephant grass was cultivated during 120 days, followed by common beans, for 75 days. In that period, contents of Zn and Pb were determined in the leachate. No Pb was found in the leachate, but Zn proved to be quite mobile in this soil. In soils treated with mill scale and filter press mud, no risk of groundwater contamination was observed, however, the 8 t ha-1 phosphate mud rate increased Zn contents in the leachate above the maximum allowed by environmental regulations. This fact limits the use of such residue for agricultural purposes. The other two residues should be evaluated in field-scale tests aiming their agricultural use.

Methods for extracting water‐soluble carbohydrates (WSC) in plants are often time‐consuming and limited to few samples per run. Aiming at resolving such restraints, the utilization of an autoclave in replacement of the traditional reflux‐based protocol was studied in completely randomized design experiments with five replicates. WSC contents were determined in stocks of 11 standards and samples of 14 grass species, following autoclave‐ or reflux‐assisted hydrolyzation. Results revealed that both methods were equally effective in recovering most standards, and plant WSC levels were similar or only narrowly lower with autoclave. Autoclave was operationally advantageous, allowing for 15‐min concurrent processing of 90 samples against a 150‐min extraction of 4 samples with reflux, and energy savings of more than 87% on a per sample basis. It is concluded that the utilization of autoclave for acidic WSC extraction is feasible and even preferable compared with reflux for the studied standards and grasses.

Methods for extracting soluble carbohydrates were compared, aiming at optimizing sample number and size, for level determination using Teles’ reagent. Oven‐dried ground stem basal segments of elephantgrass (Pennisetum purpureum, Schum.) cv. Napier, carbohydrate standards (glucose, maltose, sucrose, and starch), and sample‐standard combinations (CSs) were extracted through the following procedures: (a) REF: reflux for 180 min (in 0.6N HCl); (b) SHA: orbital shaking for 60 min (in 50% ethanol), followed by an acidic hydrolysis (1.2N HCl) in water bath (90–100°C) for 60 min, and neutralization with 5% NaOH; (c) HET: 80% ethanol overnight and water bath for 180 min; (d) ETH: 0.6N HCl (in 80% ethanol) overnight and water bath for 180 min; and (e) DIG: 80% ethanol overnight, addition of 1.2N HCl, and water bath for 60 min. REF yielded the highest extraction level in the elephantgrass sample, followed by ETH and SHA. Levels with HET and DIG were the lowest. However, REF was excessively time consuming an...

Seedlings of elephantgrass (Pennisetumpurpureum, Schum.), cvs. Vruckwona and Napier, were grown in aerated nutrient solution and exposed to pH levels of 4.0, 5.0, 6.0, or 7.0. After 30 days under controlled conditions, the effects on growth were evaluated. Plants exposed to pH 5.0, as compared to those under pH 4.0, showed increases in total leaf area, plant height, number of leaves (NL), and leaf, root, and stem fresh weight. No significant differences were found in stubble fresh weight, maximum individual leaf area, leaf area ratio (LAR), leaf area:plant height ratio, and leaf, root, stem, and stubble dry weight and dry matter percentage. Seedlings exposed to pH 4.0, as compared to those under pH 5.0, exhibited higher leaf:stem ratio on a fresh weight basis (FWR) and a tendency for higher leaf :stem ratio on a dry matter basis (DWR). Cultivar Vruckwona yielded superior results than Napier for most studied parameters, except for NL, LAR, and DWR (in which there were no significant differences) a...

RESUMO - Na conservação m vitro do capim-elefante foi observado que, ao longo dos subcultivos sucessivos de meristemas picais, ocorre gradual perda de vigor nas plântulas. Essa limitação torna necessária a reintrodução de acessos na coleção, comprometendo a eficiência do processo. Visando solucionar o problema, foi conduzido um estudo com 51 cultivares de capimelefante, onde, na repicagem efetuada a cada 4 a 6 meses, foram inoculados meristemas axilares da plântula, dispostos horizontalmente sobre meio MS, adicionado ou não de ácido naftalenoacético (ANA). Neste ciclo, que durou 45 dias, foram avaliadas as seguintes variáveis: número e comprimento dos explantes, gemas brotadas por explante, início e vigor da brotação, número de brotos desenvolvidos e percentagem de morte. Os resultados sugerem que esse método melhorou o vigor acentuadamente; embora as respostas, com e sem adição de ANA ao meio, tenham sido muito variadas entre cultivares. Apenas a cv. Mercker Comum Pinda não apresentou resposta satisfatória, devendo ser futuramente submetida a outras alternativas para propagação. Com base na produção de brotos, as cvs. Napier e Sem Pêlo apresentaram o melhor desempenho, na presença de ANA. O método mostrou-se promissor também pelo uso mínimo de reguladores do crescimento, reduzindo custos e a possibilidade de mutações. ABSTRACT - The continuous utiliwtion of explants obtainedfrom cultured apical meristems limits elephantgrass in vitro conservation because of gradual loss of vigor. Such a restriction makes it necessary to periodícally replace accessions in the coilection, reducing the efficiency of the technique. To overcome this problem, a study was carried out with 51 elephantgrass cultivars, where reculturing was conducted every 4 to 6 months using in vitro seediing axiliary meristems, with or without the addition of naphtaleneacetic acid (NAA) to the MS culture médium. During this reculturing cycle, which lasted 45 days, the following variables were evaluated: explant number and length, sprouted buds per explant, days to sprouting onset, sprouting vigor, number of developed shoots and percentage of death. The results suggest that the method improved seediing vigor markediy, altfwugh cultivar responses, regardiess of NAA addition, showed high variation. 'Mercker Comum Pinda' was the sole case showing no or weak response to either MS or NAA-enriched MS médium. Based on the number of sprouts developed, 'Napier' and 'Sem Pêlo' exhibited the best performance, when NAA was added to the médium. This method showed high potential to lower costs and reduce risks of mutations because of the limited utilization of growth regulators. Made available in DSpace on 2022-08-22T15:19:36Z (GMT). No. of bitstreams: 1 Conservacao-in-vitro-germoplasma-capim-elefante-micropropagacao-meristemas-axilares.pdf: 3008546 bytes, checksum: de8605dfc7b12dd3f83db9eb2a91e22a (MD5) Previous issue date: 1998