Gas exchange, antioxidants and foliar injuries in saplings of a tropical woody species exposed to ozone

Autor(es)

Pina, Juliana M. ^[1] ; Moraes, Regina M. ^[2]

Afiliação do(s) autor(es)

^[1] Co Tecnol & Saneamento Ambiental Sao Paulo, BR-05459900 Sao Paulo - Brazil

^[2] Inst Bot, BR-01061970 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY; v. 73, n. 4, p. 685-691, MAY 2010.
• Citações Web of Science: 20

Resumo

Ozone (O(3)) reaches phytotoxical concentrations in the tropics, but the sensitivity of tropical plant species to O(3) remains unknown. Visible foliar injuries, carbon assimilation (A(sat)), stomatal conductance, superoxide dismutase enzyme (SOD) activity and ascorbic acid concentration (AA) were evaluated in different-aged leaves of Psidium guajava `Paluma' saplings. We hypothesized that the old leaves are less capable of combating the stress induced by O(3) and hence exhibit more severe leaf injuries. Three O(3) exposure experiments were performed with `Paluma' saplings in sites with high O(3) concentration and also under filtered air conditions. The exposure experiments corresponding to the seasons spring/2006, summer and autumn/2007. The decrease of A(sat) was greater in old leaves of saplings exposed to O(3), except in the second experiment, when the AA concentrations were more pronounced than in the other experiments. In second experiment, O(3) uptake was similar to that of the first experiment, but the injuries were less severe, probably due to the high AA concentrations. It was not possible to identify a pattern of superoxide dismutase enzyme (SOD) activity due to the high variability in the results from O(3) exposed and reference saplings. O(3) uptake/A(sat) was higher in leaves exhibiting greater injury, suggesting that decrease in A(sat) may have been the main feature associated with the visible foliar symptons. (C) 2009 Elsevier Inc. All rights reserved. (AU)

• Processo FAPESP: 05/57816-6 - Respostas induzidas pelo ozônio em plantas jovens de Psidium guajava cv. Paluma
• Beneficiário: Juliana Moreno Pina
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 05/51169-9 - Respostas fisiológicas, antioxidativas e estruturais a fatores ambientais em plantas bioindicadoras sensíveis a compostos do smog fotoquímico
• Beneficiário: Marisa Domingos
• Modalidade de apoio: Auxílio à Pesquisa - Regular