Alleviation of drought stress effects on red bean by ultrasonication and foliar application of 24-epi-brassinolid

Abstract

The two-location field experiment was conducted to study the possible alleviation of droughtstress effects on red bean by ultrasonication and 24-epi-brassinolid. Locations were AgriculturalResearch Center in Shahrood, Iran and the other in bean farm, 40 km off Shahrood city in 2015.Experiment factors included irrigation of main plots at three levels of normal irrigation (60 mmevaporation from evaporation pan), mild stress (90 mm evaporation from evaporation pan) andsevere stress (120 mm evaporation from evaporation pan). Stress levels were applied after 4-leafstage and ultrasound waves treatments (in two levels of nonuse of seeds irradiation and use ofirradiation for 3 minutes at 32 °C) and 24-epi- brassinolid foliar application (in two levels ofnonuse of foliar application and foliar application at a rate of 0.1 mg/L at 50% flowering duringtwo stages) which were located in sub-plots. The evaluated properties included grain yield andcontents of superoxide dismutase, peroxidase, catalase, proline and ascorbate. The resultsshowed that with severe water stress (comparison of severe stress and lack of stress), grain yieldshowed a significant decrease in both experiment sites, however 24-epi-brassinolid foliarapplication and use of ultrasonic waves in both normal and stress conditions increased the grainyield. The same condition was established for evaluated enzymes. Thus it could be stated thatirradiation of ultrasonic waves and 24-epi-brassinolid foliar application for cultivating beansplay important role in increment of competitive strength of plant in water deficit condition.