Environmentally sustainable agriculture by elucidating the molecular mechanisms bridging plants and communities that build agroecosystems

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K22342
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 41:Agricultural economics and rural sociology, agricultural engineering, and related fields
• Research Institution: Tohoku University
• Principal Investigator: Watanabe Masao 東北大学, 生命科学研究科, 教授 (90240522)
• Co-Investigator(Kenkyū-buntansha): 南澤 究 東北大学, 生命科学研究科, 特任教授 (70167667) ; 牧野 知之 東北大学, 農学研究科, 教授 (60354106) ; 武田 和哉 大谷大学, 文学部, 教授 (90643081)
• Project Period (FY): 2019-06-28 – 2022-03-31
• Keywords: バイオマス / 栽植密度効果 / 植物ー根圏相互作用 / 遺伝子発現 / 微量金属イオン動態

Outline of Final Research Achievements

The number of seeds sown per unit area was varied in eight steps from sparse to dense. The growth was not better under the sparsest dry matter weight per seedling, but was better when the density was about two levels higher than other conditions. This effect was named the "friend effect." As causes and consequences of this "friend effect," we investigated metal ions in the soil, rhizosphere microorganisms, and genes expressed in plants. There were no characteristic changes in expressed genes and metal ions linked to the cultivation density. On the other hand, there were changes in rhizosphere microflora, and we determined that it was important to examine rhizosphere microflora changes in more detail. Similar studies were also investigated from historical documents and other sources. However, no pertinent results were obtained.

Free Research Field

植物遺伝育種学

Academic Significance and Societal Importance of the Research Achievements

日本の様に有効な農地が少なく、労働集約型農業の場合、往々にして必要播種数より多めに播種し、栽培途中で間引きを行う。間引きのタイミング・強度等は、篤農家の経験・伝承・勘に基づいており、科学的根拠に乏しい。一方、植物は幼少期、単独で生長するよりも幾つかの個体で小群落を形成した方が生長に有利であり、生育後期に過密による生長低下とは相反する。一方、先述のように従来の農作技術では対応が難しいような地球環境の変化、農業経営・栽培のグローバル化が迫っている。つまり、成育初期の小群落、間引きの科学的根拠の理解に基づく栽培法の改変ができれば、農業技術をゲームチェンジングでき、社会的な意義は大きい。