Lignin: Definition and Importance

Lignin is a complex organic polymer that is an integral part of the cell walls of plants. It provides structural support and rigidity to the plant, allowing it to stand upright and support its own weight. Lignin is particularly abundant in woody plants and is responsible for the strength and rigidity of wood.

Chemical Structure of Lignin

Lignin is composed of phenolic compounds, which are linked together in a complex three-dimensional network. The chemical structure of lignin gives it its unique properties, including its resistance to microbial degradation and its ability to provide structural support to plants.

Functions of Lignin

1. Structural support: Lignin reinforces the cell walls of plants, providing strength and rigidity.

2. Water transport: Lignin helps in the transport of water and nutrients through the plant's vascular system.

3. Defense mechanism: Lignin contributes to the plant's defense against pathogens and pests by forming physical barriers.

Study Guide

1. What is the role of lignin in plants?
2. Describe the chemical structure of lignin.
3. How does lignin contribute to the structural support of plants?
4. Explain the function of lignin in water transport within plants.
5. Discuss the role of lignin as a defense mechanism in plants.

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