Role of exogenous salicylic acid in alleviating cadmium-induced toxicity in Kentucky bluegrass

To understand the role of salicylic acid (SA) in alleviating cadmium (Cd) toxicity in Kentucky bluegrass (Poa pratensis L.), we investigated the changes of biochemical and physiological indexes in five-week-old Kentucky bluegrass seedlings exposed to 0, 5, 10 or 50 μM Cd with or without 500 μM SA for 7 d. Results showed that, compared to the Cd treatment applied alone, 500 μM SA pretreatment significantly decreased Cd accumulations and increased the chlorophyll level, growth and nutrient elements content (K, Ca, Mg and Fe) in plants, accompanying with the reduction in malondialdehyde and hydrogen peroxide contents. Furthermore, SA pretreatment enhanced remarkably the superoxide dismutase, ascorbate peroxidase and peroxidase activity in the Cd-stressed plants, but decreased catalase activity. Overall, SA might regulate the antioxidant defense activities, reduce Cd uptake and stimulate nutrient elements absorption in Cd-treated with Kentucky bluegrass, thereby improving its resistance to Cd stress.