Response reactions of Zinnia elegans seedlings to the impact of different copper ions concentrations

Abstract

The present work aims to study the responses (seed germination, root and hypocotyl size, hydrogen peroxide concentration, lipid peroxidation products, and peroxidase activity) of Zinnia elegans Jacq. seedlings to different concentrations of Cu2+ (25, 50, 100 and 200 µM). At low Cu2+ content (25-50 µM) seed germination, biomass of seedlings, and hypocotyl length did not change, but root length decreased. Under 100-200 µM Cu2+, a decrease was revealed in seed germination percentage, root and hypocotyl length, and the biomass in 8-days plants. An increase in hydrogen peroxide concentration and lipid peroxidation products, induction of apoplastic and cytosolic guaiacol peroxidase (GPOX) activity were observed in the root tissues under 50-200 µM Cu2+. The negative effects were less pronounced in the hypocotyl tissues: increase of lipid peroxidation was noted under 200 µM Cu2+, and hydrogen peroxide under 100 and 200 µM Cu2+; the activity of peroxidases did not change compared to control. Thus, the root was more sensitive to the excess of copper ions. A specific increase in the activity of apoplastic and cytosolic GPOX in root tissues can be considered as a biochemical marker for the selection of resistant forms of plants at the early stages of development. © 2021 Author(s).