Alleviation of allelopathic stress of benzoic acid by indole acetic acid in Solanum lycopersicum

The present study investigates the alleviation of allelochemical stress induced by benzoic acid (BA), an autotoxic compound, by exogenous indole acetic acid (IAA) in tomato seedlings. The experiment was conducted in hydroponic culture in glass house conditions. BA was applied 0.5 and 1.0 mM concentrations with and without IAA (1.0 mM). Root and shoot length, fresh and dry weight, pigment, protein, sugar content and nitrate reductase activity decreased in the seedlings treated with BA, while they increased in BA combined with IAA. Lipid peroxidation, electrolyte leakage and praline level enhanced in the seedlings under BA stress, but these parameters decreased in combined BA + IAA treatment. IAA protected the seedlings against oxidative stress caused by reactive oxygen species (ROS). IAA buttressed defense system of tomato plant against BA toxicity which was evident from increased activities of antioxidant enzymes. IAA has potential to enhance tolerance to stress in the tomato seedlings under allelochemical toxicity. (C) 2015 Elsevier B.V. All rights reserved.