Understanding the mechanism of pine cone opening and closing motion using novel pretreatment techniques and structural analysis

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K19203
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 40:Forestry and forest products science, applied aquatic science, and related fields
• Research Institution: Tokyo University of Agriculture and Technology
• Principal Investigator: Horikawa Yoshiki 東京農工大学, (連合)農学研究科(研究院), 教授 (90637711)
• Co-Investigator(Kenkyū-buntansha): 四方 俊幸 東京農工大学, (連合)農学研究科(研究院), 教授 (10178858)
• Project Period (FY): 2022-06-30 – 2024-03-31
• Keywords: セルロース / マトリックス成分 / 赤外分光分析 / 階層構造 / 水

Outline of Final Research Achievements

In order to understand the significance of matrix components in the opening and closing mechanism of pine cone, we have applied a novel chemical treatment technique to elucidate the mechanism. First, we established a chemical treatment method to remove non-cellulose components with maintaining the morphology of pine cone scales. Next, we conducted structural analysis from the macro- to the micro- stage and confirmed that the hierarchical structure was maintained. The bending test has been performed for pine cones. When saturated, it was similar to the untreated samples, but when oven-dried, the sample became significantly curved. The sample remained the same when re-saturated with water as when dried. These results strongly suggest that matrix components also play an important role in the bending of pine cone scales, controlling the bending angle and repeatability.

Free Research Field

木質科学

Academic Significance and Societal Importance of the Research Achievements

本研究では、新規前処理技術と構造評価によってマトリックス成分の松かさ形態変化への寄与について重要な知見を得た。明確な構造がないマトリックス成分の関与を理解するため、選択的に除去した試料の挙動を解析するという「引き算」によるアプローチは学術的意義が非常に高い。その結果、これまでセルロースの構造特性によって説明されてきた屈曲機構はマトリックス成分も屈曲角と再現性に重要な役割を果たしていることを見出だした。松かさという生物材料と水の相互作用によって駆動する天然のアクチュエーターの機構に関する知見はエコフレンドリーな次世代材料開発に弾みをつけるため社会的意義が非常に大きい。