Fig. 2
From: In situ micro-spectroscopic investigation of lignin in poplar cell walls pretreated by maleic acid
Comparison of FLIM and SRS micrographs in the same lignin droplets (a–h) and the overall fluorescence lifetime of lignin droplets after maleic acid treatment (i–l); droplets lifetime shows the overall lifetime distribution based on analysis of ~50 droplets formed under various maleic acid pretreatment concentrations. Consistently there are bimodal distributions of fluorescence lifetime that correspond to the dense and loosely packed lignin droplets. At low acid concentration (0.025 M) treatment the droplets are more diversified than at high acid concentration. Representative droplets containing loose lignin (a–d) and dense lignin (e–h) are analyzed by FLIM and SRS imaging at the same location. Line-scans are also presented under each image to show the relative intensity. Image size is 10 μm for all images