Kombine Tuz ve Nikel Stresinin Limon Otu (Melissa officinalis)'nun ROS Üretimi ve Antioksidan Enzim Aktiviteleri Üzerine Etkisi

Abstract

Plants acclimation to stress is a complex process and this complexity increase with simultaneous subjection to two or more abiotic stress. Salinity and excess accumulation of nickel are growth and development restricted abiotic stress agents. The aim of the present study was to determine the antioxidant defense system responses of Melissa officinalis (lemon balm) to salinity, nickel and their combinations. Growth, leaf osmotic potential, chlorophyll fluorescence, relative water content (RWC), lipid peroxidation, H2O2 and proline content and antioxidant enzyme activities were determined under these stress conditions. Growth and leaf osmotic potential negatively affected due to the combined effect of salt and nickel. All three stress treatments did not show any significant change on RWC and chlorophyll fluorescence in lemon balm. H2O2 content and lipid peroxidation of combined stress had greater than salt and nickel alone. Total activities of ascorbate peroxidase (APX) and glutathione reductase (GR) were increased with salt, nickel and their combinations. Moreover, the reduction in superoxide dismutase (SOD), peroxidase (POX) and catalase (CAT) activities resulted in higher lipid peroxidation and H2O2 content under the combined stress. To the best of our knowledge, this is the first study conducted on the activities of antioxidant defense enzymes of lemon balm under salinity and nickel combinations.