RESUMEN
In this study, the regulation of ascorbate peroxidase (APX) specific activity, anthocyanin, carotenoid, hydrogen peroxide, lipid peroxidation, and protein levels in cress leaves in response to different abiotic stresses were investigated. The total APX specific activity was significantly elevated after 9 days of drought treatment, short-term (2 h) exposure to 10, 100 and 370 µE of light, long-term exposure (at least 6 days) to 100 mM NaCl versus the specific APX activity in the controls. Furthermore, a significant change in total APX activity was detected in response to treatment with different temperatures; this change was an early response to 4 °C and 30 °C for a maximum of 4 h, while short-term exposure to 35 °C did not change total APX activity. The results of the present study revealed that plants have a wide range of mechanisms to cope with different stresses that possibly involve morphological changes. The results indicated that Lepidium sativum plants launch common protective pathways only under drought, salinity and high light stresses, while other protective mechanisms/strategies could be responsible for increasing the plants tolerance towards temperature and low light. Future studies will investigate changes in the photosynthetic quantum yield and specific target metabolites, proteins, and nonenzymatic antioxidants.