The response of leaf traits and photosynthetic characteristics to selenium (Se) application reflects plant adaptation strategies for selenium-enhanced accumulation of photosynthetic products. This study selected eggplant as the research subject and conducted a field experiment to better understand these relationships. This study included three Se treatments, foliar sprays of 0.5mgL-1 (T1), 1mgL-1 (T2), and 1.5mgL-1 (T3), with tap water as the control (CK). The results revealed that T1 and T2 significantly improved leaf traits and photosynthetic characteristics compared to CK, while T3 had a negative effect. Regarding the leaf area-leaf thickness (LA-LT) trade-off relationship, the T2 treatment favoured LA, whereas the CK, T1, and T3 treatments favoured LT, with trade-off values of T3>T1>CK. Regarding the net photosynthetic rate-transpiration rate (Pn -Tr ) trade-off relationship, the CK treatment favoured Tr , whereas the T1, T2, and T3 treatments favoured Pn , with trade-off values of T2>T1>T3. In T1 and T2, the eggplant specific leaf area and Pn showed non-significant and highly significant positive correlations, respectively, and in CK and T3 showed non-significant and highly significant negative correlations, respectively. These results indicate that foliar application of Se at appropriate concentrations can increase crop productivity in semi-arid areas.
