Development Of Male And Female Gametophyte

Composition of Intine and Exine Layers of a Pollen Grain

1. Exine Layer:

The exine is the outermost layer of the pollen grain. It is highly durable and helps protect the genetic material inside. The composition of the exine is:

• Made of: sporopollenin
• Sporopollenin: A tough, resistant, and chemically inert biopolymer. It is the most durable organic material known and is highly resistant to decay and decomposition.
• Function: Protects the pollen grain from environmental damage (e.g., UV radiation, dehydration) and helps it survive during transport.

2. Intine Layer:

The intine is the inner layer of the pollen grain, located beneath the exine. The composition of the intine is:

• Made of: cellulose and pectin
• Cellulose: A carbohydrate polymer that forms the structural framework of the intine layer.
• Pectin: A complex carbohydrate that helps in the adhesion and flexibility of the pollen grain.
• Function: Provides support and flexibility to the pollen grain and plays a key role during the germination process (e.g., when the pollen tube grows through the pistil).