Abstract: With the advancement of industrialization in Jilin Province, soil cadmium (Cd) pollution has posed challenges to the cultivation of ornamental horticultural plants. Hosta plants, known for their strong tolerance to Cd stress and outstandingly ornamental characteristics, could be open-field cultivated in Changchun. Taking four Hosta cultivars as experimental materials, namely H. ‘Golden Cadet’, H. ‘Blue Cadet’, H. ‘Flos Lotus’, and H. ‘Golden Tiara’, we investigated the effects of different Cd concentrations (1, 5, 50, 100, and 175 mg·kg^-1) on the growth, photosynthesis, and the antioxidant system of Hosta cultivars. By using principal component, membership function, correlation analysis and clustering analysis, Cdtolerance cultivars and evaluation indicators were screened. The contents of soluble protein and soluble sugar, as well as the activities of superoxide dismutase and peroxidase in all the four cultivars first increased and then decreased with increasing Cd concentration. Under 175 mg·kg^-1 Cd treatment, the increase in soluble sugar content of H. ‘Blue Cadet’ relative to the control was 5.3%, 2.0%, and 5.4% higher than H. ‘Golden Cadet’, H. ‘Flos Lotus’, and H. ‘Golden Tiara’, respectively. Moreover, the increases in peroxidase activity of H. ‘Blue Cadet’ relative to the control were 19% higher than H. ‘Flos Lotus’ under 175 mg·kg^-1 Cd treatment. The comprehensive evaluation value (D) of H. ‘Blue Cadet’ was consistently higher than those of other cultivars across different Cd treatments, indicating that it had the highest Cd tolerance. According to the correlation analysis under 100 mg·kg^-1 Cd treatment, four Hosta cultivars exhibited different Cd tolerance. The D value was significantly positively correlated with plant height, leaf length, leaf number, soluble protein content, and relative water content, which could be used as a key parameter for assessing Cd tolerance. In conclusion, Hosta alleviates the inhibitory effect of Cd stress on photosynthetic intensity by increasing osmoregulatory substance content and antioxidant enzyme activities, and enhancing osmotic adjustment and antioxidant capacities. Our results provide reference for the cultivation of ornamental horticultural plants and landscaping in Cd-contaminated soil in northeast China.

Key words: cadmium stress, Hosta, physiological response, comprehensive evaluation