Potato cultivation is widespread around the world, being exposed to several abiotic stresses, including soils with high aluminum (Al) availability. Silicon (Si) is recognized for alleviating the stress caused by Al in various plant species. Thus, the aim of this study was to investigate the potential of Si to mitigate the oxidative stress caused by Al in potato genotypes, exhibiting differential sensitivity toward this element. Plants of the Al-sensitive genotype (SMIJ319-7)and Al-tolerant genotype (SMIF212-3) were grown for two weeks in a hydroponic system with the nutrient solution containing combinations of Al (0 and 1.85 mM) and Si (0, 0.5 and 1.0 mM). At the end of the experiment, photosynthetic parameters, pigment content, root and shoot growth, superoxide dismutase and guaiacol peroxidase activity and lipid peroxidation were evaluated. In both potato genotypes Al BASIC AREAS -Article inhibited root and shoot growth and decreased all photosynthetic parameters and superoxide dismutase activity. Silicon was able to partially alleviate the damage caused by Al in parameters of root growth in the Al-tolerant genotype while increasing the activity of antioxidant enzymes and mitigating the Al-induced damage to membrane lipids in roots and shoot in both genotypes. The Al-tolerant genotype showed greater water use efficiency and transpiration rate in control conditions as compared to the Al-sensitive genotype. These data indicate that Si application can improve the defense ability of the tested potato genotypes against Al toxicity and that the Al-tolerant genotype is more responsive to Si.
Cadmium (Cd) is toxic to plants and animals, making it necessary to develop strategies that seek to reduce its introduction into food chains. Thus, the aim of this study was to investigate whether silicon (Si) and selenium (Se) reduce Cd concentrations in Pfaffia glomerata medicinal plant and attenuate the oxidative stress promoted by this metal. These plants were cultivated in hydroponics under the following treatments: control (nutrient solution), 2.5 μM Se, 2.5 mM Si, 50 μM Cd, 50 μM Cd + 2.5 μM Se, 50 μM Cd + 2.5 mM Si. After 14 days of exposure to treatments, leaves and roots were collected for the determination of dry weight of shoot and roots, Cd concentrations, chlorophyll and carotenoids content, and biochemical parameters (lipid peroxidation and guaiacol peroxidase and superoxide dismutase activities). The data were submitted to analysis of variance and means were compared with Scott-Knott test at 5% error probability. Roots of P. glomerata plants showed a significant reduction on dry weight accumulation when exposed to Cd. However, both Se and Si promoted a significant reduction of deleterious effects of Cd. The Cd concentrations in the tissues were reduced in the presence of Se or Si. Plants treated with Cd together with Se or Si presented higher pigment content than those with only Cd, thus showing a reduction in the negative effects caused by this element. In the treatments in which Se and Si were added in the growth medium together with Cd, an activation of superoxide dismutase and guaiacol peroxidase enzymes was observed in the roots and shoot, which may have contributed to lower lipid peroxidation. Thus, Se and Si reduce Cd concentrations and have potential to ameliorate Cd toxicity in P. glomerata plants, which can be used to increase productivity and quality of medicinal plants.
Aluminum (Al) is highly toxic to plants, causing stress and inhibiting growth and silicon (Si) is considered beneficial for plants. This chemical element has a high affinity with Al. The aim of this study was to investigate the potential of Si to mitigate the toxic effects of Al on potato (Solanum tuberosum L.) plants and assess whether this behavior is different among genotypes with differing degrees of sensitivity to Al. Potato plants of the genotypes
____________________________________________________________________________________________________________ RESUMOO estudo foi desenvolvido com base nos dados coletados em um viveiro florestal em Santa Maria, com o objetivo de realizar uma avaliação postural dos trabalhadores e das condições ambientais e estruturais do local de trabalho. A avaliação ocorreu a partir de observações visuais, além de registros fotográficos e posterior análise postural através do método RULA pelo Software Ergolân dia. Ainda, utilizou-se de entrevista informal e o censo de ergonomia de COUTO para aferições acerca dos trabalhadores do viveiro. Através das análises, evidenciou-se que as posturas empregadas no total de atividades avaliadas no viveiro não se encontram adequadas, resultando no nível 3 do método RULA, sendo necessário, portanto, intervenção ergonômica. Corroborando com tais resultados, evidenciou-se dor e desconforto nos trabalhadores, especialmente na região de coluna, pescoço, pernas e braços dos trabalhadores. O ambiente de trabalho estudado também não é condizente com o adequado para a execução das tarefas, ocasionando insatisfação entre os trabalhadores. Assim, para melhoria do ambiente, saúde e segurança, recomenda-se o uso de bancadas que permitam posturas corretas para a execução das atividades, utilização de EPIs durante as operações, evitar transporte de cargas excessivas, além de manter o revezamento de funções, diminuindo o risco de lesões por atividades repetitivas.Palavras-chave: Análise Postural; RULA; Segurança. ____________________________________________________________________________________________________________ IntroduçãoO setor de florestas plantadas no Brasil vem sofrendo uma expansão considerável desde a última década. Destacandose especialmente as espécies dos gêneros Pinus e Eucaliptus, os plantios comerciais totalizam 6,5 milhões de hectares, com uma taxa de crescimento anual de 3,5%. Na sociedade, tem sua importância ainda em termos econômicos e sociais, sendo responsável, em 2011, por um valor bruto de produção de R$ 51,8 bilhões [1].No sistema florestal, a produção em viveiro constitui a primeira etapa do processo, tornando-se o principal setor responsável pela oferta das mudas que farão parte de plantações comerciais, reflorestamentos, arborização urbana, entre outras finalidades [2]. Apesar da relevância, as operações que envolvem o preparo das mudas e implantação florestal, ainda em sua maioria são desenvolvidas de forma manual ou semimecanizada e sem condições ergonômicas apropriadas, expondo os trabalhadores a equipamentos perigosos, elevados esforços físicos e posturas inadequadas [3].Dependendo da forma como essas atividades são efetuadas, os trabalhadores ainda muitas vezes, erguem e transportam cargas com peso acima dos limites toleráveis, na forma incorreta e continuadamente por vários anos, aumentando riscos de lesão no trabalho [4]. Em virtude desse panorama, temse aumentado a preocupação com a saúde e segurança dos trabalhadores, buscando melhorias no ambiente laboral, criando...
Acidente de trabalho é toda eventualidade que ocorra e que interrompa parcial ou totalmente o desenvolvimento da tarefa, sendo então de extrema importância que seja evitado. Assim, o objetivo do estudo foi avaliar os acidentes de trabalho ocorridos nos últimos anos no Brasil, considerando diferentes setores econômicos, bem como os membros do corpo humano mais afetado por tal ocorrência. Com base em dados da previdência social, o Brasil registrou 717.911 acidentes (acréscimo de 0,55% em relação a 2012). Entretanto o número de óbitos reduziu consideravelmente desde o ano de 2000. No panorama de acidentes, a região Sul é a líder no ranking de acidentados por 100 mil habitantes. Os membros superiores são os mais afetados pelos acidentes (quase 50% do total) e as lesões na coluna vertebral também merecem destaque com 5,03% do total. Na distribuição por setores econômicos, a indústria lidera com maiores índices de acidentes, seguido pela agropecuária e por fim os serviços. A maioria desses acidentes podem ser evitar com o uso adequado de EPIs, atenção e cuidado na realização da tarefa.
The aim of this study was to perform a comparative analysis of the methods of ergonomics assessment RULA, REBA, OWAS and TOR-TOM, which the intent is to highlight similarities and differences in their use, during tillage operation with farm machinery. The study was conducted through an exploratory research in Boa Vista do Incra, RS, in August 2017, during soil preparation operation, with a tractor-subsoiler set. The operation was filmed over a period of 10 hours. After that, it was selected one hour of video, which was assumed to be representative, the video was analyzed by the methods RULA, REBA, OWAS and TOR-TOM through the software Ergolândia 5.0 and TOR-TOM, with the aid of information on noise, temperature and strength. For the comparative analyses, it was analyzed the ease of application, the importance of posture and complementary variables, and the scope of activity and postural factors. The OWAS method showed highlight in the ease of application, while the REBA and RULA methods stood out for the importance of the postural variables. For the importance of the complementary variables, RULA, followed by REBA, are worth mentioning as the most suitable. Similar results were obtained for the scope of posture factors, especially for these two methods. Regarding the scope of activity factors, the TOR-TOM obtained the most satisfactory results. Thus, the comparative analysis has highlighted the RULA method as the most suitable for postural analysis in agricultural machinery, besides the REBA method, for presenting very similar situations, contemplating full body analysis.
The aim of this work was to evaluate the effect of different concentrations of aluminum (Al) on physiological and biochemical parameters of Luehea divaricata seedlings grown in a hydroponic system under greenhouse conditions to verify the possible tolerance to Al or phytoremediation potential of this species. Seeds of Luehea divaricata were placed to germinate in commercial substrate and after 30 days the seedlings were transferred to a hydroponic system with a complete nutrient solution, pH at 4.5±0.1, with daily adjustment. After 20 days of acclimatization, homogenous plants were selected and transferred to a new nutrient solution (without phosphorus (P) and pH at 4.5±0.1) with different concentrations of Al: 0, 25, 50, 75 and 100 mg L -1 , each treatment being composed of 10 replicates of one plant each. The experiment was conducted in a completely randomized design. After seven days of exposure to the treatments, plants were collected for physiological and biochemical analyzes. Aluminum promoted a significant reduction in fresh and dry weight of roots, stems and leaves; in plant height; leaf number; leaf area; and pigment content. On the other hand, Al promoted an increase in lipid peroxidation and guaiacol peroxidase enzyme activity. Therefore, the presence of Al in the growth medium, for the studied conditions, altered significantly both physiological and biochemical parameters in Luehea divaricata seedlings, presenting a sensitive behavior to this element. Due to these characteristics, the studied species does not show phytoremediation potential.
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