Biochemical Mechanisms of Drought Resistance in Soft Wheat Under Modeling of Water Deficiency and Effects of Seed Treatment with Metabolically Active Substances

Water deficiency is one of the major factors that limit crop production among those causing plant stress. Therefore, the study aimed to investigate the effect of metabolically active compounds on reducing the negative effects of drought and stimulating physiological and biochemical processes in the spring wheat variety Provintsialka. In the study, wheat seeds were soaked in solutions of substances: PEG-6000 (EG); PEG-6000 + vitamin E (PEG+E); PEG-6000 + ubiquinone-10 (PEG+Q); PEG-6000 + methionine (PEG+M); PEG-6000 + parahydroxybenzoic acid (PEG+P); PEG-6000 + MgSO4 (PEG+Mg); PEG- 6000 + vitamin E + ubiquinone-10 (PEG+EQ); PEG-6000 + vitamin E + methionine + parahydroxybenzoic acid (PEG+EMP); PEG-6000 + vitamin E + methionine + parahydroxybenzoic acid + MgSO4 (PEG+EMPMg). The wheat seeds were then poured into a 12% PEG solution to simulate the water deficit and then germinated. The study determined the activities of ascorbate peroxidase and catalase, as well as the content of ascorbic acid and glutathione. It was found that the treatment of spring wheat seeds of the Provintsialka variety with meta-bolically active compounds and their combinations affected the activity of antioxidant protection enzymes in water-deficient conditions. Treat-ment of seeds with MgSO4 solution most effectively reduces catalase activity compared to the indicators of seedlings whose seeds were in simulated drought conditions. The treatment of wheat seeds with vita-min E most effectively stimulated the activity of ascorbate peroxidase, increasing it by 65.5% compared to the control and by 2.4% relative to the PEG treated seedlings. A decrease in the activity of catalase corre-lates with an increase in the activity of ascorbate peroxidase and indicates the compensatory effect of the enzymes of the antioxidant system. The treatment of wheat seeds with ubiquinone-10 (PEG+Q) most effectively increased the ascorbate content in seedlings by 46.3% compared to seedlings whose seeds were in water deficit conditions. An increase in the ascorbate content in wheat seedlings was also noted when wheat seeds were treated with EMP (PEG+EMP) and EMPMg (PEG+EMPMg). The highest levels of glutathione in drought-stressed seedlings were observed in those treated with vitamin E and EMP (PEG+EMP), exceeding control levels by 31.4% and 30.7%, respectively, and PEG-treated seedlings by 59.9% and 59.2%. This confirms the promising use of metabolically active substances for plant adaptation under conditions of slow water flow.