1995 Volume 45 Issue 2 Pages 151-164
Analysis of leaf morphogenesis has long been an interest for botanists. The leaf is a fundamental unit composing the metameric structure derived from the shoot apical meristem. Understanding leaf morphogenesis will help the comprehension of the overall plant morphogenesis. Also, from the point of view of plant systematics, it is worthwhile to understand the genetic backgrounds that induce the morphological differences in plants under various environmental conditions. Leaf development in dicotyledons is a complicated system which involves cell division and elongation, throughout the entire leaf. However, by using mutations in genes controlling leaf development, individual developmental pathways essential for leaf morphogenesis can be separately identified. This will provide an easy system for analysis. Recently, Arabidopsis thaliana (L.) Heynh. has been used as a model plant for morphogenetic analysis in dicotyledons. In fact, it has been successfully used in the analysis of floral development. We have isolated mutants which seem to have defect in the ontogenic process of leaf development. So far, we have unveiled the existence of genes regulating nonpolar expansion and polar elongation of the cells in the leaf, which affect its morphology. As a result, the length and width of the leaf were found to be independently regulated by these genes. Other mutants assume the possibility of different regulations in the leaf development, analysis of which is now in progress. Here we briefly review the current understanding on the leaf development. New morphogenetic analyses of leaf development in a model plant Arabidopsis are also presented.
