Sugarcane O3-fumigation experiment

Abstract

Ozone (O3) is the most toxic air pollutant with detrimental effects on plant health. Tropospheric O3 is produced by complex photochemical reactions involving biogenic volatile organic compounds (BVOCs). O3 is seasonally distributed in temperate climates, however, it occurs during the entire year with toxic concentration being registered along the whole year in tropical and subtropical climates. Most of the important agricultural crops responds to O3 stress. However, the detrimental effect of O3 is unknown in sugarcane, one of the most important crop species in Brazil, especially in the state of Sao Paulo. Inside the leaves, O3 phytotoxicity is due to the generation of reactive oxygen species (ROS). When ROS formation exceeds the antioxidant capacity of cells, an oxidative stress occurs leading to the specific structural oxidative marks and visible injuries. Based on the hypothesis that O3 levels are toxic to sugarcane plantations, the present study aims to: (i) assess the morphological, anatomical, biochemical and physiological responses of sugarcane varieties to O3. A fumigation experiment will be carried out in a free-air facility, where plants will be subject to O3 treatments and (ii) understand the BVOCs production by sugarcane varieties. During the experiment, biomass production, leaf gas exchange, photochemistry, antioxidant metabolism and structural oxidative stress marks will be evaluated. Stomatal O3 uptake will be calculated and BVOCs emission will be verified. For the first time, we will be able to understand how sugarcane reacts to O3 stress and if O3 sensitivity is genotype-dependent. (AU)