1995 Fiscal Year Final Research Report Summary
Analysis of canopy structure of multi-species plant communities
| Project/Area Number |
06454007
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
生態
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
HIROSE Tadaki Tohoku University, Graduate School of Science : Professor, 大学院・理学研究科, 教授 (90092311)
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| Co-Investigator(Kenkyū-buntansha) |
HIKOSAKA Kohki Tohoku University, Graduate School of Science : Assistant Prof., 大学院・理学研究科, 助手 (10272006)
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| Project Period (FY) |
1994 – 1995
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| Keywords | plant community / canopy structure / competition / coexistence / photosynthesis / protein / nitrogen use efficiency / multi-species system |
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| Research Abstract |
A plant communty consists of a range of species different in plant height. Tall dominant species occupying upper layrs in the canopy receive a large fraction of photon flux density, while small subordinate species occupying lower layrs receive small fractions of available photons. Tall species, however, invest relatively more biomass to supporting tissues to position their leaves high in the canopy. Thus photon absorption per unit aboveground biomass is similar between tall dominant and small subordinate species. Through the two-year study, we found : (1) In the Miscanthus sinensis stand at Kawatabi, photon absorption per unit aboveground biomass of subordinate species such as Lysimachia japonica was high early in the growing season, while that of dominant Miscanthus sinensis was high late in the growing season. This enables subordinate species to coexist with dominant Miscanthus sinensis. (2) Mixed stands of rice (C3) and millet (C4) were established in a greenhouse and competition be
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tween these species was analyzed. Although millet germinating later than rice, its growth rate was larger than rice plants. Rice reduced the growth of millet by 5%, while millet reduced the growth rate of rice up to 30%. (3) We developed a model to estimate photosynthesis of individuals in a dense stand and analyzed factors involved in the development of size hierarchy. Tall dominant plants had larger photon absorption per unit aboveground biomass and larger photosynthetic rates per unit absorbed photon flux density than suppressed plants, intensiflying the size hierarchy of the stand. (4) A model was made to analyze the effect on photosynthetic capacity of different nitrogen partitioning among photosynthetic proteins. The optimal partitioning, depending on light conditions, lead to up to 20% increase in photosynthetic efficiency. (5) We compared protein partitioning between sun (Chenopodium album) and shade (Alocasia macrorrhiza) plants. Both species had protein partitioning close to the theoretical optimum. Less
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