"Cos" it's worth it: Understanding and mitigating the impacts of ozone pollution on leafy salad crops

Ozone is a highly reactive phytotoxic molecule that causes oxidative damage to plant cells when it is taken up through the stomata. Leafy vegetation has been shown previously to be highly susceptible to such damage, although sensitivity is known to vary between different species. One of the early symptoms of ozone damage is visible injury, e.g. changes in leaf colour (chlorosis) and leaf curling (abscission), which can lead to crops harvested for their leaves such as leafy salads quickly becoming unsaleable. Increased exposure results in reduced functioning and cell death, reducing productivity and hence yield. In spite of this, the impacts of ozone pollution on sensitive crops are not well-known or understood in the agricultural community and the visible signs of damage are often overlooked or misdiagnosed.

Ozone concentrations during the main growing season are already above the damage-threshold and are projected to increase further under climate change. Additionally, crop species differ in their sensitivity to ozone and other environmental factors such as nutrient levels and irrigation, along with crop protection, can influence the magnitude of the impacts. Therefore, there is a pressing need for agronomists to be able to recognise and act on the early symptoms to mitigate against crop loss.

This project will combine chamber experiments, field observations and trials, and modelling to:

1. determine the effects of chronic and acute exposure to ozone on a range of different salad species of differing sensitivity
2. develop a diagnostic tool that agronomists can use in-field to recognise ozone damage
3. identify the mechanisms governing the sensitivity or tolerance of two selected contrasting salad species
4. quantify potential crop losses under current and future ozone pollution levels
5. identify feasible crop management practices to mitigate losses.