Drought stress is one of the most serious environmental limitations affecting the growth and productivity of plants. In the current study, oxidative damage and antioxidant responses under polyethylene glycol (PEG)-induced osmotic stress were compared in 2 melon cultivars, Kırkağaç and Galia. | Turkish Journal of Biology Turk J Biol (2013) 37: 491-498 © TÜBİTAK doi: Research Article Effect of drought stress on oxidative damage and antioxidant enzyme activity in melon seedlings 1 2, 3 3 3 Musa KAVAS , Mehmet Cengiz BALOĞLU *, Oya AKÇA , Fatma Selin KÖSE , Derya GÖKÇAY Deparment of Agricultural Biotechnology, Faculty of Agriculture, Ondokuz Mayıs University, Samsun, Turkey 2 Department of Biology, Faculty of Arts and Sciences, Kastamonu University, Kastamonu, Turkey 3 Department of Biological Sciences, Faculty of Arts and Sciences, Middle East Technical University, Ankara, Turkey 1 Received: Accepted: Published Online: Printed: Abstract: Drought stress is one of the most serious environmental limitations affecting the growth and productivity of plants. In the current study, oxidative damage and antioxidant responses under polyethylene glycol (PEG)-induced osmotic stress were compared in 2 melon cultivars, Kırkağaç and Galia. Melon seedlings were subjected to PEG-6000 solutions of 2 different osmotic potentials, – MPa and – MPa. Various physiological parameters, malondialdehyde (MDA), proline content, and antioxidant enzymes including catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) were measured. A reduction in fresh and dry weights of shoot and root tissues was observed. Significant proline accumulation was detected with increasing osmotic potential for both cultivars. A significant rise in MDA was detected in Kırkağaç at – MPa osmotic potential. In Galia hydrogen peroxide (H2O2) content increased significantly as PEG concentration increased. CAT showed significantly increased activity only at – MPa osmotic potential in both cultivars. PEG-induced osmotic stress altered GR activity in both cultivars. These results suggest that (i) Galia is more tolerant than Kırkağaç, and (ii) drought tolerance in both .
