PHYSIOLOGICAL ASPECTS OF STRESS RESISTANCE IN WINTER WHEAT

The article presents the results of long-term studies of physiological processes, oxidative stress in wheat plants under the influence of phytopathogens, mineral fertilizers and fungicides. The criteria for the damaging effect of oxidative stress are the activity of the enzyme nitrate reductase and the concentration of TBA-active products. Normally, a mobile balance is maintained between the processes of lipid peroxidation (LPO) and the antioxidant (AO) defense system of the cell. However, under stressful conditions, the ROS content in cells rapidly increases and oxidative stress develops. Plant resistance to many environmental factors is determined by the plant's ability to maintain the coordinated course of physiological processes without causing their significant disruption under conditions stress. The relationship between LPO processes and nitrate reductase activity was observed in all wheat varieties. It was found that varieties reacted differently to fertilizer doses. A high negative correlation dependence r = -83 was found between LPO and NDA processes. Many pesticides, in addition to their main target effect, have additional effects on plants. Fungicides from the triazole class (Bayleton, Tilt, Fundazol) were studied. They all showed antioxidant properties. The strongest antioxidant effect was observed for the fungicide Tilt (propiconazole). Our results, regarding the close relationship between LPO and HPA processes, make it possible to use fungicides from the triazole class for increasing plant resistance to various stress factors, activating the antioxidant system in plant cells, increasing productivity. They areas chemical immunizers, they are capable of simultaneously restraining the development of diseases and affecting physiological and biochemical mechanisms that increase the resistance of plant organisms to phytopathogens and other stress factors.