Current ambient concentrations of ozone in Panama modulate the leaf chemistry of the tropical tree Ficus insipida
Journal Publication ResearchOnline@JCUAbstract
Tropospheric ozone (O-3) is a major air pollutant and greenhouse gas, affecting carbon dynamics, ecological interactions, and agricultural productivity across continents and biomes. Elevated [O-3] has been documented in tropical evergreen forests, the epicenters of terrestrial primary productivity and plant-consumer interactions. However, the effects of O-3 on vegetation have not previously been studied in these forests. In this study, we quantified ambient O-3 in a region shared by forests and urban/commercial zones in Panama and found levels two to three times greater than in remote tropical sites. We examined the effects of these ambient O-3 levels on the growth and chemistry of seedlings of Fiats insipida, a regionally widespread tree with high stomatal conductance, using open-top chambers supplied with ozone-free or ambient air. We evaluated the differences across treatments in biomass and, using UPLC-MS-MS, leaf secondary metabolites and membrane lipids. Mean [O-3] in ambient air was below the levels that induce chronic stress in temperate broadleaved trees, and biomass did not differ across treatments. However, leaf secondary metabolites - including phenolics and a terpenoid - were significantly downregulated in the ambient air treatment. Membrane lipids were present at lower concentrations in older leaves grown in ambient air, suggesting accelerated senescence. Thus, in a tree species with high O-3 uptake via high stomatal conductance, current ambient [O-3] in Panamanian forests are sufficient to induce chronic effects on leaf chemistry.
Journal
Chemosphere
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Volume
172
ISBN/ISSN
1879-1298
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Pages Count
10
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Publisher
Elsevier
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EISSN
N/A
DOI
10.1016/j.chemosphere.2016.12.109