Food security is under increasing threat in many world regions. Rising temperatures and changes in precipitation are reducing photosynthetic efficiency and crop yields. Deteriorating air quality increasingly exposes crops to damaging levels of ozone, a powerful phytotoxin, which further reduces photosynthesis, growth and yield. These three environmental stresses occur in combination, and interactions between them can either exacerbate or ameliorate their individual impacts. This complexity is compounded as many plants have also evolved to synthesise volatile organic compounds (VOCs) as a natural defence against such stressors (Niinemets, Ü et al., 2010), but once released into the atmosphere these VOCs can themselves lead to the formation of ozone (e.g. Fuentes et al., 2000).

The student use state-of-the-art facilities to grow selected cultivars of a major global crop (oilseed rape, used for food, fodder and biofuel production, known to emit VOCs and previously reported as sensitive to ozone; Vandermeiren et al., 2012) to investigate the interactions between multiple co-occurring stressors (high temperature, drought and exposure to ozone) and the synthesis and release of protective VOCs to determine:
1. how VOC emissions differ between cultivars;
2. how VOC emissions change under individual and combined environmental stresses;
3. whether VOC synthesis enables more rapid recovery of photosynthetic capacity after removal of stress and/or limits long-term impairment of crop yield and crop quality;

We will use multi-variate regression analysis to assess the effect of these stresses on crop yield, crop quality and VOC emissions and determine the potential protective role of bVOC emissions. These experimental results will be used to develop dose-response relationships which the student will incorporate in a global emissions model (MEGAN, Model of Emissions of Gases and Aerosol from Nature; Guenther et al., 2012) to understand the wider scale impacts and implications of projected future change on crop production and food security.