Abstract: We investigated physiological responses of Prunus mume ‘Meiren’ and ‘Gu Lihong’ to drought stress and rehydration, aiming to provide scientific basis for evaluating drought resistance in Prunus mume. By applying a drought treatment, the photosynthetic and physiological parameters of potted seedlings were monitored under different drought durations (0, 7, 14, 21, and 28 days), followed by a 7-day rehydration period. The results showed that with increasing drought stress, ‘Gu Lihong’ exhibited more severe leaf wilting and yellowing than ‘Meiren’. After 14 days of drought, chlorophyll a, chlorophyll b, and chlorophyll a+b contents decreased more significantly in ‘Gu Lihong’ than in ‘Meiren’. Gas exchange parameters, including net photosynthetic rate (P_n), stomatal conductance (G_s), transpiration rate (T_r), maximal photochemical efficiency (F_v/F_m), effective photochemical quantum yield (Y(II)), and relative electron transport rate (ETR), declined progressively with drought stress in both cultivars, with a more pronounced decrease in ‘Gu Lihong’. In contrast, malondialdehyde (MDA), soluble sugar (SS), free proline (Pro), and the activities of superoxide dismutase (SOD) and peroxidase (POD) were significantly higher in ‘Meiren’. Rehydration partially restored the photosynthetic and physiological parameters of both cultivars. Drought stress inhibited photosynthesis in ‘Meiren’ leaves. ‘Meiren’ demonstrated stronger drought resistance by mitigating oxidative damage through the accumulation of osmoprotectants and the enhancement of antioxidant enzyme activity, thereby preserving membrane integrity and function under stress conditions. Overall, ‘Meiren’ exhibited greater drought resistance and resilience than ‘Gu Lihong’.

Key words: Prunus mume, drought stress, rehydration, drought tolerance evaluation