Molecular genetics of cellular differentiation in leaves

Leaves of green plants vary widely in morphology. However, the underlying cell types and structures observed in leaves of different species are remarkably similar. Although we can adequately describe leaf development in morphological terms we cannot yet explain interactions at the cellular level. In recent years molecular genetics has been used extensively to address a variety of developmental questions. The isolation of a wide variety of mutants disrupted in numerous aspects of leaf ontogeny has led to the cloning of genes involved in various developmental processes. In this review we consider advances that have been made in understanding shoot apical meristem organization, leaf initiation and the development of leaf form. In particular we concentrate on progress that has been made in understanding cellular differentiation in the epidermis, and within the interior of the leaf, namely the photosynthetic cells and the vasculature