EVALUATION OF MYCORRHIZAL INFLUENCE ON THE DEVELOPMENT AND PHYTOREMEDIATION POTENTIAL OF CANAVALIA GLADIATA IN PB-CONTAMINATED SOILS

Soil contamination by heavy metals is a serious problem to humans due to its high level of toxicity. The heavy metal lead (Pb) is commonly used in industries and if the disposal of residues that contain this element is not done properly may result in tragic consequences to the organisms. In this experiment we assessed the potential of a forrage leguminous, Canavalia gladiata, to phytoremediate lead-contaminated soil under mycorrhizal influence. The experimental design was composed of 4 Pb doses (0, 250, 500, and 1000 mg kg(-1) of soil) and the plants were inoculated or uninoculated with arbuscular mycorrhizal fungi (AMF). We observed that the nodulation was severely affected by the presence of Pb independently of the mycorrhizal status; most of the elements analyzed were affected independently of the mycorrhizal status with exception of P. The mycorrhizal colonization was able to restrict the entrance of Pb in plants under high concentrations of Pb but promoted it's accumulation in both organs under intermediate concentrations of this element. Besides the mycorrhization did not promote plant growth under Pb stress, the use of this plant may be considered to be used for phytostabilization purposes.15546547

Lead tolerance and phytoremediation potential of Brazilian leguminous tree species at the seedling stage

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)A greenhouse pot experiment was conducted to evaluate the potential of three Brazilian leguminous woody species, Mimosa caesalpiniaefolia, Erythrina speciosa and Schizolobium parahyba, for the revegetation of lead- (Pb-) contaminated areas. The response of seedlings to increasing Pb concentrations (0, 250, 500 and 1000 mg kg(-1)) in the soil was studied. In addition to Pb accumulation and translocation, the following parameters were assessed: chlorophyll, nitrate, ammonia, lipid peroxidation (MDA) and free amino acid content; seedling growth; and nitrogenase activity. No differences were observed in the germination of woody species seeds sown in soils with or without Pb addition. M. caesalpiniaefolia did not show visual symptoms of Pb toxicity, while the other two species demonstrated stress symptoms, including reduced shoot biomass yield, leaf area and height. Biochemical analyses of plant tissues revealed markedly different responses to increasing Pb concentrations, such as changes in foliar soluble amino acid composition in S. parahyba; changes in ammonia and nitrate content in E. speciosa, M. caesalpiniaefolia and S. parahyba; and changes in MDA content in S. parahyba. The levels of chlorophyll a and b and carotenoid were affected in the species studied. For the Nitrogen-fixing (N-2-fixing) species E. speciosa, an increase of Pb in the soil affected nodule formation and growth, which led to reduced nitrogenase activity in seedlings. The concentration of Pb in shoots and roots increased with the Pb concentration in soil. However, most of the Pb absorbed accumulated in the roots, and only a small fraction was translocated to aboveground parts. These findings were confirmed by the low bio-concentration factor (BCF) and translocation factor (TF) values for the three species. The tolerance index (TI) values suggested that M. caesalpiniaefolia, a N2-fixing tree, was the species that was most tolerant to high Pb concentrations in soil, while E. speciosa and S. parahyba showed moderate tolerance. Of the three Brazilian native woody species studied, M. caesalpiniaefolia was found to have the highest Pb tolerance and phytostabilisation potential in Pb-contaminated soils. (c) 2012 Elsevier Ltd. All rights reserved.110299307Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Arbuscular mycorrhiza confers Pb tolerance in Calopogonium mucunoides

Heavy metals (HMs) are environmental pollutants of great concern to humans because of their high potential toxicity. Lead is a HM that is present in the soil in very small amounts, but anthropogenic activities have increased its content in some locations, which can make these areas unproductive or inappropriate for crop production. However, there are some plants that can grow in contaminated soils and, thus, can be useful for the removal or stabilisation of such contaminants. In addition, plants that are not able to tolerate high concentrations of HMs in the soil can become tolerant or increase their performance when associated with arbuscular mycorrhizal (AM) fungi. Accordingly, this study was carried out to verify whether the inoculation of Glomus etunicatum, an AM fungus species, in Calopogonium mucunoides would influence plant tolerance to increasing concentrations of Pb in the soil. The experimental design was completely randomised, in a 2 x 4 factorial design, and the treatments consisted of inoculation (or not) with the AM fungus, G. etunicatum, and the addition of four Pb concentrations (0, 250, 500 or 1,000 mg kg(-1)) to the soil. The results showed that the association of C. mucunoides with G. etunicatum promoted biomass production, and nutrient uptake (P, S and Fe) was also positively influenced by mycorrhization. The malondialdehyde content was higher in non-mycorrhizal leaves, suggesting a reduction in the damage to membranes by lipid peroxidation in plants associated with mycorrhizae. However, the Pb concentration in the shoots did not differ between the mycorrhizal and non-mycorrhizal plants. The results of our study suggest that the AM symbiosis can be considered very effective in contributing to the tolerance of C. mucunoides to Pb.34252353

Perda dentária e expectativa da reposição protética: estudo qualitativo Dental loss and prosthetic replacement expectation: qualitative study

Esse estudo qualitativo analisou as repercussões da perda dentária total de usuários do serviço público. Aplicou-se o Oral Health Impact Profile simplificado(OHIP14) a cinquenta voluntários e, após a apuração dos resultados, foram selecionados treze pacientes para entrevistas individuais baseadas em um roteiro com questões abertas. A seleção das pessoas foi de acordo com o grau de percepção do impacto da condição bucal na qualidade de vida, medida pela pontuação OHIP, de forma a incluir a maior variedade de perfis da amostra inicial. Da análise do conteúdo dos depoimentos, verificou-se que a perda dentária total tem forte impacto na vida das pessoas e implica consequências negativas como vergonha, dificuldade em se alimentar, prejuízo ao relacionamento social e sentimento de incompletude. A possibilidade de reposição protética dos dentes gera ansiedade nas pessoas e, embora elas saibam que a utilização das próteses possa representar sacrifícios, a expectativa de retorno ao padrão social geralmente aceito e de recuperação de sua própria imagem rejuvenescida faz valer a pena quaisquer sacrifícios.<br>This qualitative research analyses the repercussions of total dental loss on people's quality of life. The Oral Health Impact Profile short-form (OHIP14) was applied to 50 volunteers, and after analyzing the results, 13 out of those 50, were selected to be individually interviewed in an opened questions script. The criteria to select these 13 people were: perception of the impact of mouth condition on quality of life measured by the score reached on OHIP. We tried to comprise the sample with a good variety, according to the profile of the initial sample. After analyzing people's statements, it was possible to verify that dental loss had strong negative consequences on people's life, like shame, difficulty to eat, impact on social relationship and feeling of not being complete. The possibility of having their teeth replaced generates some anxiety. Although being aware that wearing total prosthesis represents some sacrifices, people considered it worthwhile because the possibility of regaining the social pattern and the self-image is renewed