title: IR-SNOM analysis of occluding substances in lumina of xylem elements in sapwood of Quercus serrata attacked by Platypus quercivorus.
abstract: A new microspectroscopic technique was applied to the analysis of occluding deposits in xylem elements of Quercus serrata. The production of this substance is believed to be a defense response of the sapwood against fungal infection. An occluding substance about 10 μm across was analyzed by Infrared-Scanning Near-field Optical Microscopy (IR-SNOM), which allows for the measurement of IR spectrum with high spatial resolution. The near-field IR spectrum of an occluding substance was different from those of xylem elements and featured a lack of the clear C-H absorption band that should appear at 3000-2850 cm(-1). On the other hand, the absorption band of ester bond exhibited a very strong peak. Among the near-field IR spectra of related compounds, a similar ester absorption peak was observed in the spectrum of pectin and tannic acid. The presence of a C-H absorption band as a very week peak was similar to (+)-catechin and tannic acid.
authors.affiliation: Laboratory of Wood Chemistry, Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan. yamagishi@woodchem.fp.a.u-tokyo.ac.jp
authors.forename: Takayuki
authors.initials: T
authors.lastname: Yamagishi
authors.forename: Kento
authors.initials: K
authors.lastname: Aizawa
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Yamada
authors.forename: Yuji
authors.initials: Y
authors.lastname: Matsumoto
mesh_terms: D000818:Animals; D001517:Coleoptera / Q000502:physiology*; D008027:Light; D008853:Microscopy / Q000379:methods*; D029963:Quercus / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D014934:Wood / Q000737:chemistry*; D052584:Xylem / Q000737:chemistry*