To explore the photosynthetic characteristics of Sassafras tzumu Hemsl. under Cd stress ， the potted method was used. With 5 cadmium concentration levels（CK：0 mg·kg-1， T1：5 mg·kg-1， T2：20 mg·kg-1， T3：50 mg·kg-1， T4：100 mg·kg-1） were set， Chlorophyll content， photosynthetic gas exchange parameters and photosynthetic-light response curve of S. tzumu leaves matching each treatment were measured respectively. The results showed that：①As the concentration of Cd increased， chlorophyll a， chlorophyll b and the total amount of chlorophyll in S. tzumu leaves increased first and then decreased， the maximum was in T2. ②With the Cd concentration increased， the net photosynthetic rate（Pn） and stomatal conductance（Gs） of leaves showed a downward trend. There were no significant differences in the intercellular carbon dioxide concentration（Ci） and transpiration rate（Tr） between treatments. The photosynthetic rate of S. tzumu leaves was mainly limited by non-stomatal factors. ③With the Cd concentration increased， Pnmax（maximum net photosynthetic rate） of S. tzumu leaves decreased significantly. Under T1 processing conditions， the initial quantum efficiency（α） of S. tzumu leaves got maximum value； The dark respiration rate（Rd）， light compensation point（LCP） and light saturation point（LSP） of S. tzumu leaves decreased respectively. In conclusion， under the stress of different concentrations of Cd， the chlorophyll content of S. tzumu first increased and then decreased， which was higher than that of CK at T1 and T2， reflecting the “low promoting and high suppressing” effect of Cd stress. With the Cd concentration increased， photosynthetic gas exchange parameters and photosynthetic-light response parameters showed a downward trend compared with CK， indicating that Cd stress had an obvious inhibitory effect on S. tzumu photosynthesis.
%U https://bbr.nefu.edu.cn/EN/10.7525/j.issn.1673-5102.2021.04.005