Role of salicylic acid pretreatment in alleviating cadmium-induced toxicity in Salvia officinalis L.

Cadmium (Cd) is an environmentally polluting metal that has a negative effect on plant growth and yield. In this study, to understand the role of salicylic acid (SA) in alleviating cadmium toxicity in Sage (Salvia officinalis L.), the changes of biochemical and physiological indexes in Sage seedlings exposed to 0, 100, 200 or 300 ppm Cd with or without 0.1, 0.5 and 1 mM SA for 30 days was investigated. The results showed that Cd treatment reduced the growth, photosynthetic pigments, soluble sugars and activity of catalase and peroxidase enzymes, while increased proline content, phenolic compounds, MDA and H2O2. However, SA pre-treatment improved the growth and increased content of photosynthetic pigments, proline, soluble sugars and phenolic compounds at all levels of cadmium. Furthermore, SA pretreatment increased the activity of antioxidant enzymes catalase and peroxidase, and reduced MDA and H2O2, which reduced the cadmium-induced oxidative stress and, consequently, increased Sage tolerance to cadmium. According to our results, it seems SA might regulate the antioxidant defense activities, increase osmolyte and secondary metabolite compound in Cd-treated Sage, thereby improving growth and tolerance of Sage to Cd stress