Autor(es)

Esposito, Marisia P. ; Ferreira, Mauricio L. ; Sant'Anna, Silvia M. R. ; Domingos, Marisa ; Souza, Silvia R.

• Tipo de documento: Artigo Científico
• Fonte: Atmospheric Environment; v. 43, n. 3, p. 5-pg., 2009-01-01.

Resumo

Previous studies have reported that the extent of leaf injury in Nicotiana tabacum "Bel-W3'' exposed to environmental conditions in the city of Sao Paulo is influenced by weather conditions. This influence may occur by means of antioxidant responses. Thus, this study aimed to evaluate whether daily antioxidant responses to environmental variations interfere on the progression of leaf injury on plants of this cultivar during their exposure in a state park of Sao Paulo and to determine a linear combination of variables, among antioxidants and environmental factors, which mostly explain this visible response. Plants were exposed at the mentioned site for 14 days in four different experiments. During each experiment, three plants were daily sampled to determine the accumulated percentage of leaf area affected by necrosis and antioxidant responses (concentrations of total ascorbic acid (AA) and activity of superoxide dismutase (SOD) and peroxidases (POD)). Ozone concentrations and weather conditions were also daily measured. Pearson correlations and multivariate analyses assessed the relationship between biological and environmental variables. Leaf injury appeared between the 3rd and 6th days of exposure and increased over the exposure periods. The daily concentrations of AA tended to decrease with time of exposure in all experiments, but the activity of SOD and POD oscillated during plant exposure. Positive correlations were observed between AA or SOD and O-3 concentrations, as well as negative correlations between AA and air temperature. The increasing percentage of leaf necrosis across the whole period was explained by decreasing levels of AA 2 days before injury estimation and by higher O-3 concentrations 5 days before (R-2 = 0.36; p < 0.001). The use of N. tabacum Bel-W3 as a bioindicator can be restricted by leaf antioxidant responses to both atmospheric contamination and weather conditions. (c) 2008 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 02/04751-6 - Avaliação das respostas de bioindicadores vegetais a diferentes condições da química atmosférica envolvidas no smog fotoquímico: um estudo em câmara controlada simulando a poluição urbana
• Beneficiário: Silvia Ribeiro de Souza
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores