The researchers studied how lignin is distributed in different parts of bamboo plants. They used microscopes and special tests to look at the lignin in the plant's fibers, cells, and vessels. They found that lignin is present in all these parts, with varying amounts. Different types of lignin were also identified in the cell walls. The thickness of the layers in the fiber cell walls alternates, with higher lignin content in the thinner layers. Overall, the study shows that lignin is distributed differently in the various tissues of bamboo plants.