Abstract

This study was designed to examine and compare antioxidant and free-radical scavenging activities of leaves of six different melliferous plant species (Populus alba, Robinia pseudoacacia, Sophora japonica, Euodia hupehensis, Tilia sp.,Fraxinus sp.) from Serbia in order to evaluate their drought oxidative stress tolerance. Experiment was conducted during June, July and August. In this study, we reported the results concerning proline accumulation, soluble protein content, quantities of malonyldialdehyde, total antioxidant capacity determined by FRAP method and scavenger activity determined by DPPH method. According to our results, all melliferous plant species were subjected to drought oxidative stress during July when soil humidity decreased. During July, proline content and MDA quantity increased and soluble proteins decreased in all investigated species. High and permanent antioxidant activity during the whole investigated period was observed in P. alba, but insufficient to protect its leaves from oxidative injury during the period of drought in July. The highest ability to accumulate proline and highest protein content under severe drought stress in July was observed in Fraxinus sp. Other investigated antioxidant parameters (total antioxidant and DPPH radical scavenger capacities) were high and accumulation of MDA was low which indicate high drought oxidative stress tolerance. Therefore, highest ability to adapt under severe drought stress and highest drought oxidative stress tolerance were observed in Fraxinus sp.

Key words: Melliferous trees, lipid peroxidation, DPPH, FRAP, proline accumulation.

Abbreviation

DPPH, 1,1-Diphenyl-2-pycril-hydrasil radical; RSC, scavenging capacity; FRAP, ferric (Fe²⁺) reducing antioxidant power; MDA, malondialdehyde;ROS, reactive oxygen species; O^2•−, superoxide radical; .OH, hydroxyl radical;H₂O₂, hydrogen peroxide; RO., alkoxyl radical.