Development of the pollen grain

Inner intine wall of the pollen grain

Composed of cellulose

Dehiscence

Once the pollen grains are mature and ready to be released from the anther, the anther dries out and splits along lines of weakness. The pollen grains are exposed to the environment and can be picked up by e.g. insects

Outer exine wall of the pollen grain

A tough layer that prevents desiccation (drying out). This increases the chance of a pollen grain surviving the movement from the anther to the stigma of another flower.

Generative nucleus

Divides to form the male gametes

Tube nucleus

Forms the pollen tube

Generative cell

Has two nuclei: a generative nucleus and tube nucleus

Production

Pollen grains are produced in the anther by meiosis.

Pollen grains contain two cells

Single vegetative (non-reproductive) cell and generative cell