Effect of vermicompost fertilizer on antioxidant enzymes and chlorophyll contents in Borago officinalis under salinity stress

In order to investigate the effects of vermicompost on antioxidant enzymes and chlorophyll contents of borage (Borago officinalis) grown under salinity, a factorial experiment was conducted based on a completely randomized design with three replications. Treatments included vermicompost (0, 6, 12, and 18% of w/w soil) and four levels of salinity (0 (control), 4, 8, and 12 dS m^-1 NaCl). As salinity was increased, the activity of antioxidant enzymes (catalase, superoxide dismutase, ascorbate peroxidase, glutathione peroxidase, and malondialdehyde) increased significantly while photosynthetic pigments decreased. The use of vermicompost caused a significant increase in chlorophyllb, carotenoids and malondialdehyde contents. The maximum activities of antioxidant enzymes were obtained in the treatment with vermicompost (18%) at salinity level of 12 dS m^-1 and the highest amount of chlorophylla and total chlorophyll were obtained in the treatment with 18% vermicompost and non-salinity stress (control). Therefore, the use of vermicompost as an organic fertilizer, in addition to increasing the activity of antioxidant enzymes and the amount of photosynthetic pigments, could be a good strategy to reduce the negative effects of high concentrations of sodium and chlorine ions in soils on borage (Borago officinalis).