1997 Fiscal Year Annual Research Report

資源利用戦略からみた植物群集における競争と共存の機構

Research Project

Project/Area Number	08454248
Research Institution	Tohoku University
Principal Investigator	広瀬忠樹東北大学, 大学院・理学研究科, 教授 (90092311)
Co-Investigator(Kenkyū-buntansha)	彦坂幸毅東北大学, 大学院・理学研究科, 助手 (10272006) 酒井聡樹東北大学, 大学院・理学研究科, 助教授 (90272004)
Keywords	共存 / 競争 / 資源獲得 / 物質分配 / 環境変動 / 性投資 / シンク成長 / 両性花植物
Research Abstract	同一群落内におけるサイズの異なる個体(種)がどのように資源を獲得,利用しているかについて調べ,その共存,あるいは競争機構を解明することを目的とした.共存系として多種が安定的に存続している東北大学川渡農場のススキ群落を調べた.下層を占める種であるミツバツチグリやオカトラノオなどは上層を占めるススキに比べて吸収できる光量は非常に限られていた.しかし,葉面積が相対的に大きい形態をもつことにより,地上部重量あたりに吸収する光量は上下種で大きな差がなかった.このことは,光獲得の効率において上下層の種に差がないことを意味し,これが共存の条件であることを示唆した.競争系として,宮崎県釜房湖畔の野生のオオオナモミ群落における上層個体と下層個体の光獲得について調べた.共存系と大きく異なり,光獲得効率は上層個体で大きく,共存系との違いが明らかになった.発達段階の異なる群落の比較により,個体の高さと光条件が個体が展開できる葉面積を大きく規定していることが明らかとなった.さらに,実験圃場において窒素栄養条件の異なる群落を作り,葉の光合成特性を比較した.個葉の窒素含量は下層個体の葉ほど高い傾向を示したが,個葉における窒素の利用の仕方は個葉の光条件にのみ依存していた. サクラなど多くの植物で,結実せずに終えてしまう花がかなりあることが知られている.この一見無駄な花を着けるのは,環境条件が良く多くの花が結実可能な年に備えているからだと言われていたが,環境条件の変動が大きいほど花を少な目に着けるという戦略が進化する場合もあることを示した.動物など雌雄異体の生物において,雄の子と雌の子への進化的に安定な資源投資比は1対1となることが理論的・実証的に確かめられている.同様に,両性花植物においても,雄器官と雌器官への資源投資比は1対1となることが予測されている.しかし現実には,資源投資比は雌器官へ大きく偏ることが普通である.このことを説明するためにいくつかの仮説が提唱されたが,どの仮説も,資源投資比の大きな偏りを説明することはできなかったが,果実の生長過程におけるシンク制約成長を考慮すれば,資源投資比は雌器官に大きく偏ることを理論的に示した.

Research Products

(21 results)

All Other

All Publications (21 results)

[Publications] Hikosaka K: "Effects of leaf age,nitrogen nutrition and photon flux density on the organization of the photosynthetic apparatus in leaves of a vine (Ipomoea tricolor Cav.)grown horizontally to avoid mutual shading of leaves" Planta. 198. 144-150 (1996)
[Publications] Hikosaka K, Terashima I: "Nitrogen partitioning among photosynthetic components and its consequence in sun and shade plants." Functional Ecology. 10. 335-343 (1996)
[Publications] Hirose T, Ackerly DD, Bazzaz FA: "CO_2 elevation and canopy development in stands of herbaceous plants.In : Korner C,Bazzaz FA (eds) Carbon Dioxide,Populations,and Communities." Academic Press,San Diego. 413-430 (1996)
[Publications] Hirose T, Ackerly DD, Traw MB, Bazzaz FA: "Effects of CO_2 elevation on canopy development in the stands of two cooccurring annuals." Oecologia. 108. 215-223 (1996)
[Publications] Sakai S: "Using phylogenies to explain seed size variation among plans." Journal of Evolutionary Biology. 9. 243-252 (1996)
[Publications] Skai S: "On ovule production in environments where pollinator or resource availability is unpredictable." Journal of Theoretical Biology. 183. (1996)
[Publications] Sakai S: "Theoretical approaches on the growth strategy of plants in unpredictable environments." Plant Morphology. 8. 21-26 (1996)
[Publications] Sakai S, Sakai A: "Why is there variation in mean seed size among plants whithin single populations? Test of the fertilization efficiency hypothesis." American Journal of Botany. 83. 1454-1457 (1996)
[Publications] Hikosaka K: "Modelling optimal temperature acclimation of the photosynthetic apparatus in C_3 plants with respect to nitrogen use." Annals of Botany. 80. 721-730 (1997)
[Publications] Hikosaka K, Hirose T: "Leaf angle as a strategy for light competition : Optimal and evolutionarily stable light-extinction coefficient within a leaf canopy." Ecoscience. 4. 501-507 (1997)
[Publications] Hirose T, Ackerly DD, Traw MB, Ramseier D, Bazzaz FA: "CO_2 elevation,canopy photosynthesis,and optimal leaf area index." Ecology. 78. 2339-2350 (1997)
[Publications] Sakai A, Sakai S, Akiyama F: "Do sprouting tree species on erosion-prone sites carry large reserves of resources?" Annals of Botany. 79. 625-630 (1997)
[Publications] Sakai S, Sakai A, Ishii SH: "Patterns of wing size variation in seeds of the lily Cardiocrinm cordatum (Liliaceae)." American Journal of Botany. 84. 1275-1278 (1997)
[Publications] Anten NPR, Miyazawa K, Hikosaka K, Nagashima H, Hirose T: "Leaf nitrogen distribution in relation to leaf age and photon flux density in dominant and subordinate plants in dense stands of a dicotyledonous herb." Oecologia. 113. 314-324 (1998)
[Publications] Sakai S: "An analytical model for flower production in an environment where resource availability is unpredictable." Journal of Theoretical Biology. 189. 449-452 (1998)
[Publications] Hikosaka K, Hirose T: "Leaf and canopy photosynthesis of C_3 plants elevated CO_2 in relation to optimal Partitioning of nitrogen among photosynthetic components : theoretical prediction." Ecological Modelling. (in press).
[Publications] Hikosaka K, Hanba Y, Hirose T, Terashima I: "Photosynthetic nitrogen use efficiency leaves of woody and herbaceous species." Functional Ecology. (in press).
[Publications] Sakai S: "Does the trade-off between growth and reproduction select for female-biased sexual allocation in cosexual plants?" Evolutionary Ecology. (in press).
[Publications] Sakai S, Kikuzawa K, Umeki K: "Evolutionarily stable resource allocation for production of wind-dispersed seeds." Evolutionary Ecology. (in press).
[Publications] Sakai S, Ishii HS: "Why be completely outcrossing? evolutionarily stable outcrossing strategies in an environment where outcross-pollen availability is unpredictable." Evolutionary Ecology. (in press).
[Publications] Shitaka Y, Hirose T: "Effects of shift in flowering time on the reproductive output of Xanthium canadense in a seasonal environment." Oecologia. (in press).

1997 Fiscal Year Annual Research Report

資源利用戦略からみた植物群集における競争と共存の機構

Principal Investigator

広瀬 忠樹 東北大学, 大学院・理学研究科, 教授 (90092311)

Research Products

[Publications] Hikosaka K: "Effects of leaf age,nitrogen nutrition and photon flux density on the organization of the photosynthetic apparatus in leaves of a vine (Ipomoea tricolor Cav.)grown horizontally to avoid mutual shading of leaves" Planta. 198. 144-150 (1996)

[Publications] Hikosaka K, Terashima I: "Nitrogen partitioning among photosynthetic components and its consequence in sun and shade plants." Functional Ecology. 10. 335-343 (1996)

[Publications] Hirose T, Ackerly DD, Bazzaz FA: "CO_2 elevation and canopy development in stands of herbaceous plants.In : Korner C,Bazzaz FA (eds) Carbon Dioxide,Populations,and Communities." Academic Press,San Diego. 413-430 (1996)

[Publications] Hirose T, Ackerly DD, Traw MB, Bazzaz FA: "Effects of CO_2 elevation on canopy development in the stands of two cooccurring annuals." Oecologia. 108. 215-223 (1996)

[Publications] Sakai S: "Using phylogenies to explain seed size variation among plans." Journal of Evolutionary Biology. 9. 243-252 (1996)

[Publications] Skai S: "On ovule production in environments where pollinator or resource availability is unpredictable." Journal of Theoretical Biology. 183. (1996)

[Publications] Sakai S: "Theoretical approaches on the growth strategy of plants in unpredictable environments." Plant Morphology. 8. 21-26 (1996)

[Publications] Sakai S, Sakai A: "Why is there variation in mean seed size among plants whithin single populations? Test of the fertilization efficiency hypothesis." American Journal of Botany. 83. 1454-1457 (1996)

[Publications] Hikosaka K: "Modelling optimal temperature acclimation of the photosynthetic apparatus in C_3 plants with respect to nitrogen use." Annals of Botany. 80. 721-730 (1997)

[Publications] Hikosaka K, Hirose T: "Leaf angle as a strategy for light competition : Optimal and evolutionarily stable light-extinction coefficient within a leaf canopy." Ecoscience. 4. 501-507 (1997)

[Publications] Hirose T, Ackerly DD, Traw MB, Ramseier D, Bazzaz FA: "CO_2 elevation,canopy photosynthesis,and optimal leaf area index." Ecology. 78. 2339-2350 (1997)

[Publications] Sakai A, Sakai S, Akiyama F: "Do sprouting tree species on erosion-prone sites carry large reserves of resources?" Annals of Botany. 79. 625-630 (1997)

[Publications] Sakai S, Sakai A, Ishii SH: "Patterns of wing size variation in seeds of the lily Cardiocrinm cordatum (Liliaceae)." American Journal of Botany. 84. 1275-1278 (1997)

[Publications] Anten NPR, Miyazawa K, Hikosaka K, Nagashima H, Hirose T: "Leaf nitrogen distribution in relation to leaf age and photon flux density in dominant and subordinate plants in dense stands of a dicotyledonous herb." Oecologia. 113. 314-324 (1998)

[Publications] Sakai S: "An analytical model for flower production in an environment where resource availability is unpredictable." Journal of Theoretical Biology. 189. 449-452 (1998)

[Publications] Hikosaka K, Hirose T: "Leaf and canopy photosynthesis of C_3 plants elevated CO_2 in relation to optimal Partitioning of nitrogen among photosynthetic components : theoretical prediction." Ecological Modelling. (in press).

[Publications] Hikosaka K, Hanba Y, Hirose T, Terashima I: "Photosynthetic nitrogen use efficiency leaves of woody and herbaceous species." Functional Ecology. (in press).

[Publications] Sakai S: "Does the trade-off between growth and reproduction select for female-biased sexual allocation in cosexual plants?" Evolutionary Ecology. (in press).

[Publications] Sakai S, Kikuzawa K, Umeki K: "Evolutionarily stable resource allocation for production of wind-dispersed seeds." Evolutionary Ecology. (in press).

[Publications] Sakai S, Ishii HS: "Why be completely outcrossing? evolutionarily stable outcrossing strategies in an environment where outcross-pollen availability is unpredictable." Evolutionary Ecology. (in press).

[Publications] Shitaka Y, Hirose T: "Effects of shift in flowering time on the reproductive output of Xanthium canadense in a seasonal environment." Oecologia. (in press).

広瀬忠樹東北大学, 大学院・理学研究科, 教授 (90092311)