engleski

Antioxidative response in pepper leaves to salt stress

In greenhouse growing, plants are often exposed to unfavorable growth conditions due the salt stress. The aim of this research was to examine the influence of NaCl applied into the substrate on the physiological stress response parameters in leaf tissue of pepper cultivar "Quadrato d'Asti Rosso".All the examined stress parameters were significantly influenced by NaCl treatment. Guaiacol-peroxidase total activity and peroxide concentrations were increased proportionally with the intensity of the salt stress and the maximum values determined at 200 mM NaCl. Lipid peroxidation level, total catalase and glutathione-reductase activity increased up to 100 mM NaCl. Treatments with 100 mM NaCl and 200 mM NaCl did not show any statistically significant differences. The highest proline content was determined at 200 mM NaCl, while at 50 mM NaCl, proline content was significantly higher as compared to the control and 100 mM NaCl. Specific activity of catalase was significantly enhanced with 100 and 200 mM NaCl. The highest specific activity of the guaiacol-peroxidase was seen in the treatment with 200 mM NaCl, and significantly higher than the values measured at levels up to 100 mM NaCl. The specific activity of the glutathione-reductase increased significantly at 50 and 100 mM NaCl, with an unexpected decrease in activity at the highest level of stress. These results suggest that the short exposure of pepper plants to salt stress in the root zone, activates different physiological mechanisms of defense against oxidative stress in the leaf tissue.

salt stress ; NaCl ; pepper ; antioxidative enzymes ; lipid peroxidation

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