Effect of nano-TiO2 foliar application on ear yield and activity of some antioxidant enzymes of sweet corn under water deficit stress

In order to investigate the effects of water deficit stress and nano-TiO2 foliar application on ear yield and activity of some antioxidant enzymes in sweet corn plant, an experiment was conducted in split plot form based on RCBD in three replications at the Research Station of the Islamic Azad University, Tabriz Branch, during growing seasons of 2017. Treatments were water deficit stress in three levels contained: 50, 75 and 100% filed capacity (FC) as well as the nano-TiO2 foliar application in four levels contains: non application (control), 0.01, 0.03 and 0.05%. The analysis of variance showed significant effect of water deficit stress on catalase (CAT), hydrogen peroxide (H2O2), water relative content (RWC), ear yield (p<0.01) and ascorbate peroxidase (APX) (p<0.05). Also, effect of nano-TiO2 foliar application in all studied traits (p<0.01) and interaction effects between water deficit stress and nano-TiO2 foliar application except for water relative content in other studied traits (p<0.01) was significant. 0.01% Nano-TiO2 increased catalase and ascorbate peroxidase enzymes and decreased hydrogen peroxide in all treatments, however, 0.01% nano-TiO2 foliar application under 50% FC irrigation had the highest activity of catalase, ascorbate peroxidase and lowest levels of hydrogen peroxide. Furthermore, 0/01% nano-TiO2 foliar application under 100% FC irrigation as compared to the non TiO2 foliar application under 50% FC and control increased ear yield by 58 and 8.1%, respectively. Generally, 0.01% nano-TiO2 foliar application under 50% FC irrigation was able to increase the activity of enzymes associated with the reduction of stressful effects and eventually, the yield of the ear was increased in similar conditions and did not use this combination.