Oxidative Response of Groundnut (Arachis hypogaea) Plants to Salicylic Acid, Neem Oil Formulation and Acalypha fruticosa Leaf Extract

Plants are always under threat due to various biotic and abiotic stresses. They respond to such threats by an efficient antioxidative system. A series of experiments were carried out to study the effect of exogenous application of Salicylic Acid (SA), Acalypha fruticosa chloroform leaf extract and Neem Oil formulation (NO) on the induction of antioxidative enzymes such as Peroxidase (POD), Polyphenol Oxidase (PPO) and on total phenols, hydrogen peroxide (H2O2) and protein contents in groundnut plants. Twenty day-old plants were sprayed with SA (0.014 and 0.028%), A. fruticosa extract (1.0%) and NO (0.2, 0.5 and 1.0%). Water treated plants were maintained as control. A considerable increase in the oxidative enzyme activities, total phenols and protein contents was observed at 24, 48, 72 and 96 h after treatment. A quick response was shown by plants to A. fruticosa (1.0%) application. Extract of A. fruticosa (1.0%) induced maximum enzyme activities (13.1 IU g-1 FW POD and 0.48 IU g-1 FW PPO, respectively, at 96 h after treatment). Moreover, total phenols, H2O2 and protein contents were also high in A. fruticosa treated plants followed by those treated with NO (1%). These findings showed that A. fruticosa extract and neem oil influenced the metabolic system in plants and induced the oxidative response that could defend plants against a variety of stresses.