1. Department of Chemistry, Faculty of Science and Mathematics, University of Niš, Višegradska Street No 33, 18000 Niš, Serbia
2. Department of Plant Physiology, Faculty of Biology, Sofia University “St. Kl. Ohridski”, 8 Dragan Tzankov Blvd., 1164 Sofia, Bulgaria
3. Department of Biology and Ecology, Faculty of Science and Mathematics, University of Niš, Višegradska Street No 33, 18000 Niš, Serbia