Volatile and non-volatile secondary metabolites are compounds stepping in protection against biotic and abiotic stress by improving survival in environment. Isoprene is the mainly volatile secondary metabolite emitted by plants. It could be a protection against oxidative damage caused by ROS, produced during a water stress, for instance. Moreover, isoprene can react with NOx to form tropospheric ozone or be oxidized to form aldehydes or ketones in the atmosphere. Non-volatile secondary metabolites, such as phenolic compounds, especially flavonoids, are known to protect plants against heat stress.
With global change, models plan an increase of summer drought in mediterranean region for the end of this century. We can expect an increase of temperatures (+3.4°C) and a decrease of natural rain (-30%). With these new environmental conditions, plants could invest more in secondary metabolites production compared to primary metabolites (such as sugars...) and growth, according to ecological theories. These potential modifications can have consequences on health and growth of forests but also, on air quality. My PhD subject is to characterize these potential changes to determine the behavior of Quercus Pubescens in front of global change.