1. ; Department of Plant Sciences, Faculty of Science; The University of Tokyo; Hongo, Bunkyo-ku Tokyo 113 Japan
2. ; Global Environment Division; National Institute for Environmental Studies; Tsukuba Ibaraki 305 Japan
3. ; Institute of Biological Sciences; University of Tsukuba; Tsukuba, Ibaraki 305 Japan
4. ; Department of Biology; The University of Tokyo; Komaba, Meguro-ku, Tokyo 153 Japan