Effect of salicylic acid on the anti-oxidative system of Bt and non - Bt cotton grown in semi-arid soils of Nizamabad

The effect of salicylic acid (SA) sprayed in three concentrations viz., 0.5 mM, 1.0mM and 3.0mM on the antioxidative system comprising of antioxidative enzymes [catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), glutathione reductase (GR) and super oxide dismutase (SOD)] as well as antioxidants like ascorbate (ASA) and reduced glutathione (GSH) were analyzed in two varieties of cotton (Gossypium herbaceum L.) viz., Bt- cotton and non-Bt plants grown in the semi-arid tropics of Nizamabad. The soil in Nizamabad district is saline and black soil wherein the plants usually experience drought and saline stresses. Application of all three concentrations of SA positively increased the activities of all the enzymes (catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR) and super oxide dismutase (SOD) in the two varieties of cotton compared to untreated control plants except peroxidase (POD) enzyme activity which was found decreased. Further SA was found to increase the contents of ascorbate (ASA) as well as reduced glutathione (GSH). The Bt-cotton variety showed better performance over non-Bt varieties. SA at 3.0 mM conc. was found most effective in increasing enzymes as well as  antioxidants in both cotton varieties over 1.0mM, 0.5 mM and untreated controls. The promotion of enzyme contents as well as antioxidants in both cotton varieties is an indicator that SA mitigated the negative effect of the semi-arid soil conditions of Nizamabad district.