Leaves are determinate structures whose primary function is to produce carbohydrates required for plant growth and development.
Leaves display a wide range of genetically and developmentally regulated variation in shape.
The leaf lamina is initiated and first appears as lateral projection on the adaxial half of the leaf primordium. Various growth patterns of leaf expansion have often been explained by the pattern of cell division. The variation in the amount of expansion within the plane of lamina lead to much of the diversity of leaf shape. Because of the morphological simplicity and accessibility of the leaves, growth control, pattern formation and cell differentiation can all be conveniently studied in the context of leaf development. The nal1 mutant exhibited narrow cotyledons, and short hypocotyl and roots in early seedling development.