Objective: In this study, the effect of different concentrations of cadmium pollution on physiological and biochemical characteristics of Cinnamomum camphora seedlings was investigated, which aims to reveal the response mechanism of photosynthetic and other physiological characteristics of C. camphora under cadmium stress, so as to provide data accumulation and scientific basis for the remediation of contaminated soil. Method: In this study, an indoor pot experiment was conducted with one-year-old C. camphora seedlings that were subjected to 4 treatments of different contents of cadmium in contaminated soil, including 0 mg•kg-1 (CK), 1 mg•kg-1 (Cd1), 10 mg•kg-1 (Cd2) and 30 mg•kg-1 (Cd3), and each treatment had 5 replicates. Samples were collected and analyzed on days 0, 15, 30, and 60. The photosynthetic characteristics parameters, the contents of chlorophyll, proline, soluble sugar, soluble protein, malondialdehyde (MDA), and the activities of superoxide dismutase (SOD) and peroxidase (POD) of C. camphora seedlings were tested to explore the tolerance of C. camphora to cadmium and its potential and feasibility for phytoremediation. Result: The net photosynthetic rate (Pn) of C. camphora leaves did not change significantly under different concentrations of cadmium pollution in 0-15 days. Pn of the seedlings treated with contaminated soil for 30 days and 60 days was lower than that of the control, and Pn of seedlings treated with high Cd2+concentration (Cd3) was the lowest with an average deceases of approximate 22.33% compared with that of the control. In addition, the content of chlorophyll in C. camphora under different concentrations of cadmium contaminated soils decreased, and chlorophyll in medium and high concentrations of cadmium (Cd2 and Cd3) significantly reduced. The content of proline (Pro), soluble sugar and soluble protein in C. camphora leaves was increased by cadmium pollution of different concentrations, and the content was the highest under high concentration Cd2+ stress (Cd3). After 30 days and 60 days, the activity of SOD in medium and high concentration cadmium treatment (Cd2 and Cd3) was significantly higher than that in the control as well as low concentration cadmium stress. During the whole treatment period, POD activity increased with the pollution time and the cadmium concentration. However, the medium and high concentration cadmium stress had a significant effect on the increase of MDA content. Conclusion: The results suggest physiological and biochemical indexes of C. camphora, such as the photosynthesis parameters, osmotic adjustment substances and antioxidant protective enzymes, are closely related to stress time and pollution concentration. But, C. camphora seedlings grow well under different concentrations of cadmium stress, reflecting that C. camphora has strong cadmium tolerance and thus has potential value for remediation of heavy metal contaminated soil. © 2020, Editorial Department of Scientia Silvae Sinicae. All right reserved.
