Physiological Response of Casuarina equisetifolia Seedlings to Cd Contaminated Soil after Passivating Treatment

In June 2019, 1-year bare-root Casuarina equisetifolia container cutting seedlings were planted on pure Cd contaminated soil (CK), +5% of straw biochar, +5% of peat and +5% of attapulgite. 5 months after treatment, determinations were implemented on diameter and height growth, content of MDA, soluble sugar and soluble protein. The results showed that height and ground diameter growth reached more than 2.5 and 14 time of the initial value, showing strong adaptability to Cd stress. MDA content of seedlings on treated soil was 39.3%, 84.1% and 94.3% of that on the control. Multiple and cluster analysis demonstrated that adding 5% of straw biochar had the best passivation effect.