Investigating the potency of ethylenediurea (EDU) in alleviating the affliction of ambient ozone in heat labile tomato cultivars (Solanum lycopersicum L.).

Tomato is the second most valuable vegetable crop, and its susceptibility to tropospheric ozone (O) varies on the cultivar. Eight tomato cultivars with documented O sensitivity were reevaluated using ethylenediurea (400 ppm EDU) to determine the effectiveness of EDU in assessing O sensitivity under heavily O-polluted tropical conditions. EDU helped in amending the growth, photosynthetic pigments, photosynthetic rate, stomatal conductance, and yield characteristics in the tomato cultivars. EDU reduced the lipid peroxidation and reactive oxygen species content, while enzymatic and non-enzymatic antioxidant responses differed across cultivars. The cultivar Superbug and Sel-7 (O susceptible) performed better by employing more biomass and yield and exhibiting more potent antioxidative defense machinery mainly non-enzymatic antioxidants after EDU treatment. The higher value of total antioxidative potential (TAP) in O susceptible cultivars suggested the adaptive resilience through EDU application against O stress. EDU application greatly enhanced the photosynthetic rate in O susceptible cultivars by increasing the stomatal conductance. Hence, both biophysical and biochemical responses were involved in protection against O provided by EDU. Kashi chayan and VRT02 (O tolerant) cultivars showed least response to EDU, due to their efficient inherent mechanisms in alleviating O stress. Thus, EDU may be used as an efficient biomonitoring tool against O-sensitive cultivars.