Genotypic differences in some physiological parameters symptomatic for oxidative stress under moderate drought in tomato plants

Water stress strongly affects horticultural cultivars, reducing yield and fruit quality. Also the physiological functions of the plant are altered by this stress, due fundamentally to the formation of reactive oxygen species and water relationships. This study examines the response of five cherry tomato varieties to oxidative stress generated by moderate water deficit. Our results indicate that the cultivar Zarina is more tolerant to this stress, registering greater biomass and leaf relative water content (LRWC), associated with high antioxidant activity and low content in osmoprotective compounds. Also, we found a positive correlation of relative growth rate (RGR) total and foliar with LRWC, and a negative one with the parameters malondialdehyde (MDA), H2O2, test antioxidants, phenolic content, proline and quaternary ammoniums compounds (QAC), indicating the importance of lipid peroxidation as the determinant physiological process in selecting tomato plants tolerant to water stress.