Effects of exogenous calcium on Bermuda grass under simultaneous stress of cadmium and acid rain

Acid rain and heavy metal cadmium (Cd) pollution are global environmental problems affecting plants. Plant priming with calcium (Ca) alleviates various environmental stresses. However, the mitigation effect of exogenous Ca on Bermuda grass has not been evaluated under the dual stress of Cd and acid rain. This research was designed to explore the effect of 5 mmol/L Ca on the growth of Bermuda grass seedlings under the combined stress. The results showed that exogenous Ca improved the growth indicators including root length, plant height, stem length, leaf length, root dry weight, stem dry weight, leaf dry weight and total dry weight, reduced the MDA content, and increased the relative chlorophyll content, SOD, POD and CAT activity, and N, P, K contents in different organs. The alleviating effect of exogenous Ca was be limited by acid rain intensity. Exogenous Ca had a significant alleviating effect on plants under combined stress of Cd and pH4.5 acid rain, and promoted the Cd uptake in plants. This research provided a scientific basis for further understanding the positive effects of exogenous Ca on plant growth under the combined stress of Cd and acid rain, and phytoremediation of soil Cd pollution in acid rain areas.