Zhi Chang Chen1, Jian Feng Ma2. 1. Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki, Japan. 2. Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki, Japan. Electronic address: maj@rib.okayama-u.ac.jp.