| Co-Investigator(Kenkyū-buntansha) |
KAKEHASHI Masayuki Hiroshima Univ. Medicine Instructor, 医学部, 助手 (80177344)
INOUE Ken Shinshu Univ. General Education Assistant Professor, 教養学部, 助教授 (40176425)
OHARA Masashi Hokkaido Univ. Agriculture Instructor, 農学部, 助手 (90194274)
IWASA Yoh Kyushu Univ. Science Professor, 理学部, 教授 (70176535)
YAHARA Tetsukazu Univ. of Tokyo General Education Assistant Professor, 教養学部, 助教授 (90158048)
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| Research Abstract |
Three different types of mating systems are known in angiosperms, i. e., (1) obligate xenogamy (or outbreeding), (2) facultative xenogamy (or autogamy), and (3) obligate autogamy. In the present research project, the roles of different breeding systems for the production of offsprings and their evolutionary significance for population differentiations were investigated from theoretical as well as empirical standpoints. New evidences obtained from experimental studies and also field observations were also examined in the light of new models and theories presented in the present studies.
1. Previous population genetical models. and Lande-Schemske's model predicted the evolutionary advantages of a mating strategy, i. e., facultative autogamy, but its evolutionary implications were re-examined based on the results obtained by examining the roles of abortion, inbreeding depression, cost of outbreeding, differentiation patterns of autogamy at the population level.
2. Examples were presented based upon the studies on Campanula punctata, C. microdonta, Trillium differentiations in mating systems, outcrossing rates, and sex allocation patterns.
3. The roles of offspring recruitment by cleistogamous and chasmogamous flowers in such plant species with dimorphic reproductive systems as Ainsliaea fauriana, A. abiculata, and Leibnitzia anandria were examined in field and experimental popualtions. Controlling mechanisms of CH and Cl seed production under various environmental regimes were also anlyzed.
4. Autogamous system of Sceptridum (Ophioglossaceas) was examined and compared with that of anagiosperms.
5. Based upon all these new evidence and theoretical frameworks, the roles of autogamous mating systems in plants for population differentiations were examined discussed.
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