Microscopic characterization of tension wood cell walls of Japanese beech (Fagus crenata) treated with ionic liquids

Published Date
Micron
September 2016, Vol.88:24–29, doi:10.1016/j.micron.2016.05.007

Author 

• Toru Kanbayashi ^a,b
• Hisashi Miyafuji ^b,,

• aDepartment of Wood Improvement, Forestry and Forest Products Research Institute, Tsukuba, Japan
• bGraduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan

Received 15 March 2016. Revised 16 May 2016. Accepted 22 May 2016. Available online 24 May 2016. 

Highlights

• •
  Morphological and chemical features of tension wood treated with ionic liquids were described.
• •
  Cell walls in tension wood were swollen by ionic liquid treatment.
• •
  Changes in tissue structure were different for normal wood and tension wood.
• •
  Chemical changes in gelatinous layers were different for the types of ionic liquids.

Abstract

Tension wood that is an abnormal part formed in angiosperms has been barely used for wood industry. In this study, to utilize the tension wood effectively by means of liquefaction using ionic liquid, we performed morphological and topochemical determination of the changes in tension wood of Japanese beech (Fagus crenata) during ionic liquid treatment at the cellular level using light microscopy, scanning electron microscopy and confocal Raman microscopy. Ionic liquid treatment induced cell wall swelling in tension wood. Changes in the tissue morphology treated with ionic liquids were different between normal wood and tension wood, moreover the types of ionic liquids. The ionic liquid 1-ethyl-3-methylimidazolium chloride liquefied gelatinous layers rapidly, whereas 1-ethylpyridinium bromide liquefied slowly but delignified selectively. These novel insights into the deconstruction behavior of tension wood cell walls during ionic liquid treatment provide better understanding of the liquefaction mechanism. The obtained knowledge will contribute to development of an effective chemical processing of tension wood using ionic liquids and lead to efficient use of wood resources.

Keywords

Biorefinery

Cell wall

Gelatinous layer

Ionic liquid

Liquefaction

Tension wood

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• ⁎ 
  Corresponding author at: Division of Environmental Sciences, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Hangi-cho, Shimogamo, Sakyo-ku, Kyoto 606-8522, Japan.

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