Exogenous application of penconazole regulates plant growth and antioxidative responses in salt-stressed Mentha pulegium L

Abstract

The mechanism of growth amelioration in salt-stressed pennyroyal (Mentha pulegium L.) was investigated by exogenous application of penconazole (PEN). Seven weeks after sowing, seedlings were treated with increasing NaCl concentrations (0, 25, 50, and 75 mM) writh or without PEN (15 mg 1−1) and were harvested randomly at different times. Results showed that some growth parameters and the relative water content (RWC) decreased under salt stress, while lipid peroxidation, H2O2content, activities of Superoxide dismutasc (SOD; EC 1.15.1.1), peroxidase (POX; EC 1.11.1.7), polyphenol oxidase (PPO; EC 1.10.3.1), catalasc (CAT; EC 1.11.1.6), and ascorbatc peroxidase (APX; EC 1.11.1.1) remarkably increased. Exogenous application of PEN increased some growth parameters, RWC, antioxidant enzyme activities, and H2O2content, but the effects of PEN were more significant under salt stress conditions. PEN treatment also decreased lipid peroxidation. These results suggest that PEN-induccd tolerance to salt stress in M. pulegium plants may be related to regulation of antioxidative responses and H2O2level.