Lignin - GCSE Biology Definition

Lignin is a complex organic substance found in the cell walls of some plant cells, making them rigid. It is present in the cell walls of the xylem vessels, which transport water and ions through the plant, as well as in wood and bark. Lignin acts like a glue, binding together cellulose fibres and providing structural support. It allows plants to transport water efficiently and to remain strong and upright, even in harsh weather conditions. In GCSE Biology, understanding lignin is part of understanding plant structure and how plants adapt to their environments.