Conditions for the preparation of water-soluble conjugates by modification of polyvinyl alcohol with a natural antioxidant vanillin or synthetic from the class of sterically hindered phenols have been developed. Estimation of growth-stimulating activity of conjugates was carried out on wheat seeds of variety Leningradskaya 97. It was established that presowing wheat seeds treatment of conjugates with antioxidant activity at optimal concentrations (0.1%) enhances root formation and positively influences the accumulation of seed weight, thereby increasing plant resistance to unfavorable factors environment.