Abstract
Angiosperm leaves generally develop as bifacial structures with distinct adaxial-abaxial polarity. In contrast, several monocot species, such as iris and leek, develop unifacial leaves, in which leaf blades have only abaxial identity. The development and evolution of unifacial leaves have long been matters of debate. However, genetic mechanism underlying unifacial leaf development remains totally unknown.
We are studying unifacial leaf development using Juncus prismatocarpus (Juncaceae) as a model. We established mutant isolation system in J. prismatocarpus and isolated 7 mutants with abnormal adaxial-abaxial polarity. These mutants commonly showed adaxialized leaf sheath phenotype, and the leaf sheath was completely adaxialized in the most severe line. On the other hand, the leaf blade never showed adaxialization phenotype even in the most severe line and remained to be abaxialized. These mutants also showed abnormalities in the floral organs and in the internodes. In this presentation, we report histological and gene-expression analyses in these mutants, and discuss the genetic mechanism underlying leaf blade abaxializaiton in unifacial leaves.
