A new model of ozone stress in wheat including grain yield loss and plant acclimation to the pollutant

Surface ozone (O₃) is an important air pollutant globally and enhanced concentrations lead to crop yield penalties in many parts of the world. Crop models simulate production and yield and they are often used for various applications. However, most of the existing models neglect the effect of O₃ and only limited parameterization schemes exist. In addition, the existing O₃ modelling approaches do not take into account the plant acclimation to the pollutant as a mechanism of survival and maintenance of performance. Here, we introduce a simple modelling method to simulate the O₃ damage to wheat with consideration of the plant acclimation process. The O₃ parameterization scheme was incorporated into the GLAM-Parti crop model, resulting in a new model version GLAM-ROC (i.e. GLAM – Relative Ozone Concentrations). The new model simulates the effect of O₃ on crop growth and development and was evaluated against data from control-environment chambers with high O₃ concentration levels and variable duration of exposure to the pollutant. GLAM-ROC successfully reproduced the observed plant response to O₃ as well as the final biomass and yield. The incorporation of plant acclimation allowed the prediction of crop yield loss at variable duration of O₃ exposure. The statistical response formula neglected the acclimation process and overestimated the relative O₃ damage to yield by 56.5%, when fumigation increased from 32 to 106 days. We conclude that the plant acclimation to chronic O₃ environment is significant and should be taken into account for the effect of O₃ on wheat performance and yield.