title: Direct mapping of morphological distribution of syringyl and guaiacyl lignin in the xylem of maple by time-of-flight secondary ion mass spectrometry.
abstract: Lignin, one of the main structural polymer of plant cell walls, varies in amount and monomeric composition among tissue and cell types, as well as among plant species. However, few analytical methods are available that can conveniently and accurately determine the morphological distribution of lignin units at the cellular level. In this report, we used time-of-flight secondary ion mass spectrometry (TOF-SIMS) to directly map guaiacyl (G) and syringyl (S) lignin units in several successive growth rings of the maple xylem. TOF-SIMS imaging and a semiquantitative approach revealed clear difference in the annual distribution of lignins between the fiber and vessel. While the vessel walls were constantly G-rich with varied S/G ratios through a growth ring, the fibers showed fairly regular annual distribution of lignins in which the earlywood was S-rich with an almost constant S/G ratio and the latewood was G-rich resulting from a decrease of the S unit. The reliability of TOF-SIMS results was demonstrated by its high correlation with the results of thioacidolysis on radial distribution of the S/G ratio in several contiguous tree rings and also in the latewood and earlywood of each ring. These results indicate that TOF-SIMS allows direct visualization of lignin composition in plant tissues.
authors: Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
authors: Kaori
authors: K
authors: Saito
authors: Yoko
authors: Y
authors: Watanabe
authors: Manabu
authors: M
authors: Shirakawa
authors: Yasuyuki
authors: Y
authors: Matsushita
authors: Takanori
authors: T
authors: Imai
authors: Takayoshi
authors: T
authors: Koike
authors: Yuzou
authors: Y
authors: Sano
authors: Ryo
authors: R
authors: Funada
authors: Kazumi
authors: K
authors: Fukazawa
authors: Kazuhiko
authors: K
authors: Fukushima
mesh_terms: D031002:Acer / Q000737:chemistry*; D008031:Lignin / Q000737:chemistry*; D018629:Spectrometry, Mass, Secondary Ion / Q000379:methods*; D014934:Wood / Q000737:chemistry; D052584:Xylem / Q000737:chemistry*
chemical_list: C434470:guaiacyl monolignol; C434469:syringyl monolignol; D008031:Lignin