Ozone stomatal flux model applied to a tropical tree species: incorporation of the action of volatile organic compounds in O3 removal

Abstract

The concentration of ozone (O3) has increased worldwide threatening species and ecosystems. Plants act as O3 sinks via stomatal and non stomatal processes. Non stomatal processes include the removal of O3 molecules of the boundary layer that cover the leaf by volatile organic compounds (VOC) emitted by plants. Many studies have attempted to the development of critical levels of vegetation protection against the effects of O3. It was found that indexes based on stomatal conductance and environmental factors produce more accurate results that indexes based on the concentration of O3 in the air. The objective of this project is incorporate the action of volatile organic compounds emitted by Astronium graveolens Jacq., a tropical tree species sensitive to O3, in the O3 stomatal flux model to verify if this increases its predictive capacity. Saplings of A. graveolens will be exposed to ambient conditions for six months in a place contaminated by O3. Daily courses of stomatal conductance will be performed weekly. On the same days, VOC will be collected and analyzed by gas chromatography with detection by mass spectrometry. Climate and air quality will be monitored continuously. The model accuracy will be assessed by a dose x response curve considering O3-induced foliar injury as the response variable, providing a subsidy for public policies to the control of air quality. (AU)