Fig. 6
Quantitative analysis of SRS images of lignin in secondary xylem cell walls in poplar. a Image settings. Intensity analyses for specific types of cell walls can be performed in Fiji software. Open the selected picture and change the image to 8 bit. b Calculate the average photon counts for all measurements. Click on “Analyze” and select “Histogram” to calculate the average photon counts for all measurements. c, d Obtain the ratio of the intensity value. Click on “List” to view the intensity values and counts. The total intensity values will be divided into 256 parts. From the 0 to 255 value, the intensity counts will be calculated for every tenth value. Then the ratio of the intensity value will be obtained by dividing the sum of ten counts by the total counts. e, f Calculate the average intensity for selected cells. For each type of plant sample, at least three images were selected for intensity analysis. About 50 cells were selected for further analysis. Click on “Analyze” and select “Measure” to calculate the average intensity for selected cells. Lignin (1600 cm−1) signals in each pixel are plotted