Abstract
We have proposed that the two-dimensional growth of leaf blade is controlled, at least in part, by polar cell expansion. On the other hand, contribution of cell division orientation in the determination of leaf shape has been unclear. To further understand the molecular basis of leaf morphogenesis, we characterized an Arabidopsis leaf-shape mutant, angustifolia3 (an3). Wild-type and an3 leaves were similar in length, while the width of an3 leaves was narrower than that of wild-type leaves. Leaf cell shape (ratio of cell length versus cell width) in an3 is not significantly different from that of wild-type plants. In contrast, the number of leaf cells was reduced preferentially in the leaf-with direction when compared to that of wild-type plant. These observations suggest that the cell division orientation in the leaf-with direction and the leaf-length directions are controlled by different mechanisms. Progress of positional cloning of AN3 gene will also be presented.
