Abstract
In Japan, dwarf forms are known to have evolved in various species of plants which habit in old temples/shrines or islands such as Miyajima, Yakushima, and Kinkazan islands. For elucidating how those dwarf forms are fixed genetically, we selected plantains (Plantago asiatica) as a model plant, and established 36 lines of non-dwarf and dwarf plantains. Comparison of leaves of non-dwarfs and dwarfs revealed that number of cells was decreased in dwarf forms. Since alteration of cell size was not observed, a change in cell proliferation might be responsible for the small size of leaves in dwarf forms. Then, we looked for conditions to induce decrease in cell number in Arabidopsis thaliana and found out a clue in ethylene response. We will discuss a possibility that induction of dwarf phenotype by ethylene might contribute to genetic fixations of dwarf forms in natural environments.
