Is biodegradation of leaf-litter strongly regulated by the occurrence of lignin?

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K07468
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Forest science
• Research Institution: Hokkaido University
• Principal Investigator: Koda Keiichi 北海道大学, 農学研究院, 講師 (80322840)
• Research Collaborator: Miyamoto Toshizumi
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: lignin / leaf / litter / biodegradation / microorganisms / nitrobenzene oxidation / methoxy group

Outline of Final Research Achievements

A novel method applicable to determination of lignin content of tree leaves was developed and proposed. The validity and reliability of this method was confirmed by the comparison with the conventional methods such as Klason and acetyl bromide methods, using wood and leaf samples. It was shown that this method was applicable to leaf samples from conifer and broad-leaved trees, and that lignin contents of leaf samples were found much lower than those obtained by the conventional methods. This method was further applied to field experiments, using leaf litter. Lignin itself was not necessarily the most important rate-limiting factor affecting biodegradation of oak leaf litter, because it was found that oak leaf litter was decomposed in accordance with its lignin at a similar rate. Our results also showed that other environmental factors such as nitrogen influx could affect the degradation of leaf litter.

Free Research Field

森林圏科学／木質科学／木材化学

Academic Significance and Societal Importance of the Research Achievements

本研究で提案したリグニン定量法は、リグニンに特徴的な基本構造に着目した定量法であり、妨害物質の影響により従来の方法ではリグニンの定量が困難な試料、特に樹木の葉のみならず、草本類などの非木材試料に対しても適用できる可能性が高いと考えられ、今後の検証が必要である。また、その上で、高等植物ばかりでなく、維管束組織の発達が未熟な段階にある植物体に対して適用した場合、リグニンの存在が植物体に対して果たしている役割の進化論的な意義づけにも、有用な手法になる可能性がある。