The researchers studied how corn stalk lignin changes during a special treatment process. They used a chemical called 1,4-dioxane and acid to extract the lignin. Advanced imaging showed that lignin is removed first from the inside of the cell wall and then moves outward. By analyzing the extracted lignin, they found that more of one type of building block (syringyl) is removed first, while another type (guaiacyl) increases as the treatment goes on. This shows that lignin from different parts of the cell wall has different structures.