Determining the Syringyl/Guaiacyl Lignin Ratio in the Vessel and Fiber Cell Walls of Transgenic Populus Plants

Abstract

Observation of the spatial lignin distribution throughout the plant cell wall provides insight into the physicochemical characteristics of lignocellulosic biomass. The distribution of syringyl (S) and guaiacyl (G) lignin in cell walls of a genetically modified Populus deltoides and its corresponding empty vector control were analyzed with time-of-flight secondary ion mass spectrometry (ToF-SIMS) and then mapped to determine the S/G lignin ratio of the sample surface and specific regions of interest (ROIs). The surface characterizations of transgenic cross-sections within 1 cm vertical distance of each other on the stem possess similar S/G lignin ratios. The analysis of the ROIs determined that there was a 50% decrease in the S/G lignin ratio of the transgenic xylem fiber cell walls.