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13,804,000 Yen
¡¡High species diversity in the tropical forest ecosystem is based on high level of speciation. Speciation occurs as a result of the accumulation of genetic variation within species, i.e., intraspecific variation. However, few information is available for the intraspecific variation of wild plants in tropical forest ecosystem. Therefore, we analyzed isozyme variation of some leguminous plants (Vigna sp.) collected in tropical ecosystem to examine whether the level of isozyme variation of plants in tropical ecosystem is higher than that of the same or closely related species collected in subtropical ecosystem (the Nansei Archipelago) . As a result, we obtained data showing that the level of isozyme variation was not significantly different between tropical and subtropical ecosystem.
¡¡Species diversity in tropical forest ecosystem become possible based on the difference of life strategy. Nitrogen fixation of leguminous plants is an important factor concerning with their life strategy. Therefore, we tried to estimate the variability of nitrogen fixing ability of leguminous tree species in Pasoh by natural 15N abundance method. Low ¦Ä15N value of non-leguminous seedlings (average = -0.07) indicated low ¦Ä15N value of soil surface in Pasoh. It is difficult to estimate nitrogen fixation under this condititon. ¦Ä15N value of tall leguminous tree was 5.19. This may indicate higher ¦Ä15N value in lower soil layer, and suggest the possibility of estimating nitrogen fixing ability of tall leguminous trees in Pasoh.
Leguminous Plants, Intraspecific Variation, Isozyme, Interspecific Variation, Nitrogen Fixing Ability