Abstract: [Objective] This study aimed to study the physiological and ecological response characteristics of Lycium barbarum to elevated atmospheric CO₂ concentration() in Ningxia, and to provide a theoretical basis for exploring the cultivation and breeding of wolfberry and other woody economic forests under the background of climate change.[Method] In this study, ‘Ningqi No.1’ cuttings were used as experimental materials, the changes of plant vegetative growth index, fruit morphological parameters, sugar content, active substance content and sucrose metabolism-related enzymes activity of fruits in response to elevated were determined by using an open-top chamber (OTC) experimental facility and equipped with a concentration automatic monitoring system to simulate and control.[Result] 1) The increase of by 0.5 times[(570±20) μmol·mol^-1] and 1 times[(760±20) μmol·mol^-1] significantly promoted the growth of L. barbarum plants. The net growth of seedling height was 11.67% and 18.65% higher than that of the control, and the ground diameter was 55.09% and 62.58% greater than that of the control, respectively. 2) Under the two elevated treatments, the transverse diameter of L. barbarum fruit in Ningxia increased by 4.56% and 7.71% respectively, and the weight of single fruit increased by 15.05% and 34.53% respectively, compared with the control. 3) Under the two elevated treatment, the fructose content of summer fruits (90 d after treatment) was slightly higher than that of CK, while that of autumn fruits (120 d after treatment) was 1.39% and 3.98% lower than that of control. During the treatment period, the contents of glucose and total sugars were lower than those in CK, especially under treatment with 1 times. The content of sucrose in summer fruits was lower than CK under the two treatments, but the autumn fruits were slightly higher than that of control fruits when the CO₂ concentration increased by 1 times. 4) The content of polysaccharides decreased compared with CK flavonse decreased 16.62% and 18.35% in autumn fruits, and the increase of by 1 times had greater impact. 5) Changes in the activity of sucrose metabolism-related enzymes of fruit were obvious with the two elevated treatments. Acid invertase and neutral invertase increased. Sucrose phosphate synthetase in the summer fruits increased significantly, but autumn fruit enzyme activity was lower than that in control. The change trend of enzyme activity in decomposition direction and synthesis direction was the same. During the summer period, they were all higher than the control, but in the autumn period lower than the CK.[Conclusion]Thus, long-term treatment with elevated promotes vegetative growth of L. barbarum, increases the weight of single fruit, vertical diameter and horizontal diameter, which is helpful to improve the appearance of fruits. However, the content of sugar and bioactive substances such as polysaccharides and flavonoids are significantly reduced, and the activity of sucrose metabolism-related enzymes activity changes, which affected the nutritional quality of fruits.

Key words: Lycium barbarum, elevated CO₂ concentration, nutritional quality, polysaccharides, sucrose metabolism-related enzymes