Ameliorating impact of exogenously applied of methanol and nano TiO2 on antioxidant enzymes and seed oil of borage under water shortage

Abstract The aim of the present investigation was to determine ameliorating impact of exogenously applied of methanol and nano TiO2 on antioxidant enzymes and seed oil of borage, under water shortage. Therefore, this study was conducted in 2012 as a split factorial on the basis complete randomized block design with four replications in the city of Shahriyar in Iran. Treatments consisted of no stress (once every 7 d) and deficit irrigation (once every 14 d) in the main plots; 0% (control; sprayed with water), 15%, 35% and 45% (v/v) concentrations of methanol aqueous solution; and 0, 0.01%, 0.03% and 0.05% titanium dioxide nanoparticle concentrations applied to the sub-plots. Deficit irrigation increased the activity of antioxidant enzymes, the oil percentage and MDA, but decreased protein content, and seed and oil yield. The binary interaction effects of deficit irrigation and methanol and the interaction of deficit irrigation and nano-TiO2 were significant for all traits except oil percentage. Foliar application of methanol and nano TiO2 sprays individually had the highest protein content and seed and oil yield, especially in the stress condition. The application of methanol and nano TiO2 individually under deficit irrigation showed the highest activity for antioxidant enzymes and the least for MDA. The lowest antioxidant enzymes was achieved by 45% (v/v) methanol and no application of nano TiO2 under no stress irrigation; however, this concentration produced the lowest seed and oil yield. The 45% v/v concentration of methanol treatment under deficit irrigation, performed best with higher oil yield, protein and antioxidant enzymes.