Pioneer plant growing at an old mine site could provide a safe site for tree seedlings via enhancing infection of functional microbes

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K20473
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 64020:Environmental load reduction and remediation-related
• Research Institution: Forest Research and Management Organization (2023); Hokkaido University (2021-2022); Japan Atomic Energy Agency (2019-2020)
• Principal Investigator: Haruma Toshikatsu 国立研究開発法人森林研究・整備機構, 森林総合研究所, 任期付研究員 (40836417)
• Project Period (FY): 2019-04-01 – 2024-03-31
• Keywords: ススキ / アカマツ / 内生菌 / 重金属 / 鉱山跡地

Outline of Final Research Achievements

At an ole mine site, Miscanthus sinensis and Pinus densiflora can grow naturally, showing that they are useful for revegetation. Although P. densiflora sprouts (seedlings) were growing healthily inside M. sinensis, the leaves of P. densiflora outside M. sinensis were brown, indicating that the growth of the plants had been inhibited. Because microorganisms growing in roots contribute to heavy metal stress tolerance in plants, microorganisms were isolated from roots of M. sinensis and P. densiflora seedlings. As the results, common microorganisms were isolated. In addition, measurement of soil temperature showed that daily soil temperature change (diurnal range) were smaller inside M. sinensis than outside. These results suggest that M. sinensis could promote establishment of P. densiflora seedlings in old mine sites by sharing microorganisms and reducing diurnal range in soil temperature.

Free Research Field

環境生態化学

Academic Significance and Societal Importance of the Research Achievements

日本の高度成長を支えた鉱山の多くは、現在操業が停止している。そのため、国内には多くの鉱山跡地があり、付近住民の安全の他に環境・景観などの観点から、その緑化が強く望まれている。従来ススキなどの草本はアカマツ等樹木の侵入・定着を妨げるとされてきた。しかし本研究は、鉱山跡地のような強い環境ストレス下では、ススキがアカマツ実生の生育を促進し、定着に寄与する可能性を示唆した。これらの結果は、特定の条件下では草本が樹木の定着を促進することを示しており、今後の鉱山や荒廃地などの緑化技術という社会的ニーズの高い技術に対して基礎的な知見を提供すると考えられた。