AbstractLight provides crucial positional information in plant development, and the morphogenetic processes that are orchestrated by light signals are triggered by changes of gene expression in response to variations in light parameters. Control of expression of members of the RbcS and Lhc families of photosynthesis-associated nuclear genes by light cues is a paradigm for light-regulated gene transcription, but high-resolution expression profiles for these gene families are lacking. In this study, we have investigated expression patterns of members of the RbcS and Lhc gene families in Arabidopsis (Arabidopsis thaliana) at the cellular level during undisturbed development and upon controlled interference of the light environment. Members of the RbcS and Lhc gene families are expressed in specialized territories, including root tip, leaf adaxial, abaxial, and epidermal domains, and with distinct chronologies, identifying successive stages of leaf mesophyll ontogeny. Defined spatial and temporal overlap of gene expression fields suggest that the light-harvesting and photosynthetic apparatus may have a different polypeptide composition in different cells and that such composition could change over time even within the same cell.