The different intensity ultrasound effect on the antioxidant status of lentil seedlings in a condition of hypothermia

Abstract

Background. The study of the ultrasound effect on plant organisms is a promising direction in biophysical and physiological-biochemical research. Most of the research concerns the pre-sowing treatment of seeds to improve their germination. Only a few studies consider the effect of ultrasound on the activity of antioxidant enzymes. No information has been found on the effect of ultrasound on the plant organism under stressful conditions. The purpose of the work is to study the different intensity ultrasound effect on the work of enzymes of the antioxidant system, the activity of lipid peroxidation reactions under optimal temperature conditions and under the action of hypothermia (+3 °C). Materials and methods. The object of the study is 14-day-old seedlings of lentils of the Rauza variety. Experimental options included exposure to ultrasound of different intensities, 0.4 and 1 W/cm2, using an ultrasonic transducer UZT-10.1F. Hypothermia was created by placing the seedlings in a low-temperature cabinet for 1 hour at a temperature of +3 °C. Superoxide dismutase activity was determined by the reduction reaction of nitro blue tetrazolium triggered by riboflavin; peroxidase activity – by the time of formation of a blue color as a result of benzidine oxidation; catalase activity – by spectrophotometric method; the content of malonic dialdehyde – by color reaction with thiobarbituric acid when heated. Determination of the content of auxins was carried out by the method of a biological sample and was expressed in μg-equiv of IAA/g dry weight. Results. Under optimal temperature conditions, a significant increase in the activity of superoxide dismutase was noted, regardless of the intensity of ultrasound. Under the conditions of the action of a stressor, a greater activity of the enzyme was revealed under the action of low-intensity ultrasound. Under optimal conditions, this intensity increased the activity of catalase and peroxidase to a greater extent, compared with the high one. Under conditions of hypothermia, ultrasound with an intensity of 0.4 W/cm2 stimulated the work of catalase and peroxidase, but to a lesser extent than under optimal conditions. The activation of the studied enzymes under the action of ultrasound was observed against the background of an increase in the content of endogenous auxins. Under the conditions of the action of the stressor, a significant inhibition of the reactions of lipid peroxidation under the influence of ultrasound was revealed. The studied levels of ultrasound intensity did not affect the mass of the aerial organs of lentil seedlings, but promoted the growth of the root system.

Keywords

• ultrasound
• hypothermia
• superoxide dismutase
• catalase
• peroxidase
• malondialdehyde
• auxins
• lentil seedlings