Effect of Methanol on the Activity of Antioxidant Enzymes, some Compatible Osmolytes and Biochemical Traits of Wheat under Cut off Irrigation Conditions

In order to investigate the effect of methanol on the activity of antioxidant enzymes, some compatible osmolytes and biochemical traits of wheat under cut off irrigation conditions, the present experiment as factorial was conducted based on randomized complete blocks design with three replications at the research farm of Faculty of Agriculture and Natural Resources of University of Mohaghegh Ardabili, during 2015-2016 cropping year. The investigated factors were included irrigation levels (full irrigation as control, cut off irrigation in 50 percent of spike stage and cut off irrigation in 50 percent of the booting stage (pregnancy) as mild and sever water restriction, respectively; according to codes 55 and 43 of the BBCH scale) and methanol foliar application at four levels (foliar application with water as control and foliar application 10, 20 and 30 percent by volume of methanol). The results showed that foliar application of 30 percent by volume of methanol under full irrigation conditions increased 42.83, 36.01, 29.69, 57.93 and 49.98 percent of chlorophyll b content, total chlorophyll, carotenoids, protein percentage and grain yield and decreased hydrogen peroxide and malondialdehyde content 75.58 and 63.77 percent, respectively; in comparison with non-foliar application under cut off irrigation at the booting stage. Foliar application of 30 percent by volume of methanol under cut off irrigation conditions in booting stage increased proline and soluble sugars content (125.42 and 91.93 percent, respectively) in comparison with non-foliar application of methanol under full irrigation conditions. Also, foliar application of 30 percent by volume of methanol under full irrigation conditions decreased the activity of antioxidant enzymes (catalase, peroxidase and polyphenol oxidase). It seems that foliar application of 30 percent by volume of methanol can increase grain yield of wheat under cut off irrigation conditions due to improving biochemical traits.