Cadmium stress affects cucumber seedlings' photosynthesis and chlorophyll fluorescence. Lower cadmium levels mainly impact stomatal function, while higher levels also affect chlorophyll content and PSII reaction. On the 8th day, nonstomatal limitations like decreased chlorophyll content become more significant. The study shows that cadmium stress leads to a decline in photosynthetic rates, stomatal conductance, and chlorophyll content in cucumber seedlings.