Chlorophyll a fluorescence induction kinetics (CFI) is an important tool that reflects the pho?tosynthetic function of leaves, but it remains unclear whether it is affected by leaf structure. Therefore, in this study, the leaf structureCFI curves of sunflowersorghum seedlings were analyzed.Results revealed that there was a significant difference between the structures of palisadespongy tissues in sunflower leaves. Their CFI curves, measured on both the adaxialabaxial sides, also differed significantly. However, the differences in the leaf structuresCFI curves between both sides of sorghum leaves were not significant. Further analysis revealed that the differences in the CFI curves between the adaxialabaxial sides of sunflower leaves almost disappeared due to reduced incident light scatteringrefraction in the leaf tissues; more importantly, changes in the CFI curves of the abaxial side were greater than the adaxial side. Compared to leaves grown under full sunlight, weak light led to decreased differences in the CFI curves between the adaxialabaxial sides of sunflower leaves; of these, changes in the CFI curvespalisade tissue structure on the adaxial side were more obvious than on the abaxial side. Therefore, it appears that large differences in sunflower leaf structures may affect the shape of CFI curves. These findings lay a foundation for enhancing our understanding of CFI from a new perspective.