Age-dependent modulation of antioxidant defense and secondary metabolite accumulation in Solanum lycopersicum under...

The rapid rise in tropospheric ozone (O₃) concentrations has emerged as a pressing environmental concern, casting a looming shadow on agroecosystems worldwide. This study investigated the effect of elevated O₃ on biochemical, morphological, and yield characteristics of Solanum lycopersicum (tomato), a vital global crop. During the experimental period, the average O₃ concentrations were 54.37, 69.31, and 84.31 ppb for ambient (AO), and elevated ozone (EO₁ and EO₂) doses. The results of the study reveal a clear escalation of oxidative stress in tomato. Reactive oxygen species (ROS) production increased by (29.94-47.32)% and (44.16-67.41)% and malondialdehyde (MDA) accumulation by 18.28% and 30.93%, at EO₁ and EO₂ O₃ doses, respectively, as compared to control (AO). The enzymatic antioxidant activity and the secondary metabolite production showed significant upregulation at both doses of elevated ozone as compared to ambient ozone (control). Whereas the antioxidant activity showed higher increments during the vegetative phase, secondary metabolites escalated prominently during the reproductive phase. Elevated O₃ doses caused significant reductions in plant growth and biomass, and reproductive traits, at both EO₁ and EO₂ concentrations, as compared to control. Substantial yield reductions of 17.33%, and 36% were recorded at EO₁ and EO₂ O₃ doses, respectively, as compared to control. This study highlights the urgent need to unravel plant mechanistic responses towards rising O₃ levels, which will assist in developing management strategies for O₃-induced productivity losses in horticultural crops, thereby safeguarding agricultural sustainability and food security in a changing climate.