ORIGINAL ARTICLE

Effect of Exogenous Abscisic Acid on Seed Germination and Growth of Winter Wheat Seedlings Under Zinc Stress

Among heavy metals, zinc is essential for plant growth and development. It plays an important role in metabolism, is critical for the action of Zn-dependent enzymes involved in physiological processes. However, at elevated concentrations, like other heavy metals, it negatively affects the plant metabolism. In this work, we investigated whether priming with abscisic acid alters the physiological responses of winter wheat seeds and seedlings under zinc stress. It was shown that at elevated concentration, zinc treatment decreased seed germination of winter wheat varieties Podolyanka by 17%. When 10^-6 M ABA solution was applied the seed germination increased by 13.5%. Zinc inhibited the growth of shoots and roots of seedlings. The roots were more sensitive to the action of zinc. The negative effects of the metal  leveled by ABA adding, and on the seventh day, a stimulating effect of the hormone on root growth was recorded. Incubation in zinc solutions had a negative effect on the fresh biomass accumulation by wheat seedlings. During transition of plants from the heterotrophic to autotrophic feeding the dry biomass reduced, but on the seventh day the vegetation on the mixture of hormone – heavy metal solutions some growth decrease and maximum dry biomass occurred. Thus, exogenous application of ABA somewhat reduced the negative effects of zinc on seed germination and root growth of winter wheat and improved protection against heavy metal toxicity.