Exhaustive survey of understory herbaceous plants obtaining organic carbon through arbuscula mycorrhizal networks.

• Project/Area Number: 18K19356
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 45:Biology at organismal to population levels and anthropology, and related fields
• Research Institution: Yamagata University
• Principal Investigator: Yokoyama Jun 山形大学, 理学部, 教授 (80272011)
• Co-Investigator(Kenkyū-buntansha): 富松 裕 山形大学, 理学部, 教授 (40555398)
• Project Period (FY): 2018-06-29 – 2021-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥6,240,000 (Direct Cost: ¥4,800,000、Indirect Cost: ¥1,440,000); Fiscal Year 2020: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2019: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000); Fiscal Year 2018: ¥3,380,000 (Direct Cost: ¥2,600,000、Indirect Cost: ¥780,000)
• Keywords: 安定同位体 / 栄養摂取様式 / 菌根菌ネットワーク / 菌従属栄養植物 / 森林群集 / 部分的菌従属栄養 / アーバスキュラー菌根菌 / 安定同位体比 / 夏緑樹林 / 林冠木 / 独立栄養植物 / 有機炭素

Outline of Final Research Achievements

Many green orchids and pyroloids have been found to be partially mycoheterotrophic (i.e. mixotrophic) feeding on ectomycorrhizal fungi associated with surrounding trees. Whereas many fully mycoheterotrophic plants feed on arbuscular mycorrhizal (AM) fungi, the prevalence of mixotrophy in AM plants is still debated. We investigated 13C and 15N isotopic abundances of understory plants, canopy trees, and AM fungi in a Japanese temperate forest to explore potential mixotrophic understory plant species. Our results suggest that isotopic abundances are of limited help in finding potential mixotrophs that feed on AM fungi, even though mixotrophic species, if any, are likely to be enriched in 13C.

Academic Significance and Societal Importance of the Research Achievements

ラン科とツツジ科では、外生菌根菌に依存する部分的菌従属栄養植物が多く見出されており、炭素の安定同位体比が主要な根拠となってきた。一方、大多数の植物種がアーバスキュラー菌根菌（AM菌）と共生しているにも関わらず、AM菌に依存する部分的菌従属栄養植物は積極的に探索されてこなかった。本研究では、部分的菌従属栄養植物の新たな特定には至らなかったが、安定同位体比の有効性と限界について、詳細な検討を行うことができた。

Research Products

• [Journal Article] Isotopic evidence of arbuscular mycorrhizal cheating in a grassland gentian species. (2020)
  • Author(s): Suetsugu, K., Matsubayashi, J., Ogawa, N.O., Murata, S., Sato, R. and Tomimatsu, H.
  • Journal Title: Oecologia Volume: 193
  • Peer Reviewed
• [Presentation] アーバスキュラー菌根菌に炭素源を部分的に依存する林床植物の安定同位体分析による探索. (2019)
  • Author(s): 村田怜, 橋本靖, 山岸洋貴, 横山潤, 富松裕
  • Organizer: 日本生態学会東北地区会第64回大会（盛岡）
• [Presentation] Isotopic analysis of plants in a temperate forest community: Do any understory plants extract carbon from arbuscular mycorrhizal fungi? (2019)
  • Author(s): Murata, S., Hashimoto, Y., Yamagishi, H., Yokoyama, J., Tomimatsu, H.
  • Organizer: International Symposium on Rapid Evolutionary Change of Invertebrates, Plants, and their Interactions under Ecological Disturbance
  • Int'l Joint Research
• [Presentation] アーバスキュラー菌根菌から有機炭素を得る林床植物の安定同位体分析による探索 (2019)
  • Author(s): 村田怜, 橋本靖, 山岸洋貴, 横山潤, 富松裕
  • Organizer: 第66回日本生態学会大会
• [Presentation] 夏緑樹林における植物群集とアーバスキュラー菌根菌の安定同位体分析 (2018)
  • Author(s): 村田怜, 橋本靖, 山岸洋貴, 横山潤, 富松裕
  • Organizer: 第50回種生物学シンポジウム