Abstract: Taking five rose varieties including Soeur Emmanuelle, Red Devil, Chocok, Mountain sunrise, and Alpine flame as meterials, during the growing season, the growth vigor of each variety was observed, and changes in physiological and biochemical indicators were measured during the natural cooling process in winter. These indicators included relative conductivity, malondialdehyde (MDA) content, soluble sugar and starch content, as well as the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and phenylalanine ammonia-lyase (PAL). The aim was to clarify the relationship between cold resistance and these physiological and biochemical indicators in different rose varieties. The results showed that only Alpine flame and Mountain sunrise could overwinter normally in Jilin Province, and had a relatively long flowering period. As temperatures decreased, the relative conductivity of all varieties initially increased, then decreased, and then increased again. The MDA content generally showed an upward trend. At -11 ℃, Alpine flame and Mountain sunrise exhibited lower relative electrical conductivity values (68.58% and 70.83%, respectively), indicating that these two varieties could better withstand low temperatures, with less electrolyte leakage and milder cell membrane damage compared to the other three varieties. However, Chocok had an MDA content as high as 88.13 μmol/g at 12 ℃, indicating it could no longer grow normally at this temperature. Proline and soluble sugar content generally increased, while starch content initially rose and then declined. The soluble sugar content of Red Devil and Chocok was consistently significantly lower than that of the other three varieties, indicating weaker resistance to low temperatures. The activities of SOD, POD, CAT, and PAL in all varieties initially increased during the early stages of cooling, demonstrating their role in cold resistance.

Key words: Rosa hybrida, variety, cold resistance, physiological mechanism