XVI International Botanical Congess

Leaf index, relative length of leaf to width, is one of the most diverse factor of leaf shape. For instance, rheophytes are characterized by narrow leaves, which represent an adaptation to their habitats. However, the genetic control of development of these shapes have remained unclear. Focusing on mechanisms that govern polarized growth of leaves in a model plant, Arabidopsis thaliana, we found that the two genes act independently to each other on the processes of polar growth of leaves: the AN gene regulates width of leaves and the ROT3 gene regulates length of leaves. These two genes specifically control the polar elongation of leaf cells. Based on the results from analyses of these genes, molecular mechanisms related to the evolution of leaf shape will be discussed.