Pollination and fertilisation

Reproduction · Sexual reproduction in plants · note 3 of 5

Spec 16.3.5, 16.3.6, 16.3.12Download all Sexual reproduction in plants notes (PDF)Download all notes (PDF)8 pages

Pollination and fertilisationSpec 16.3.5, 16.3.6, 16.3.12

In short

Pollination is the transfer of pollen grains from an anther to a stigma, and fertilisation occurs when a pollen nucleus fuses with a nucleus in an ovule. Pollination must happen first. A pollen tube then grows from the pollen grain down through the style into an ovule, carrying the pollen nucleus to fuse with the egg cell nucleus.

Pollination is the transfer of pollen grains from an anther to a stigma. Pollination is not the same as fertilisation. Pollen has to reach the stigma first, then fertilisation can happen.

Fertilisation occurs when a pollen nucleus fuses with a nucleus in an ovule.

Pollination: The transfer of pollen grains from an anther to a stigma.
Fertilisation (in plants): The fusion of a pollen nucleus with a nucleus in an ovule.

Supplement

Supplement: only for the Extended papers (2 and 4). Core students can skip it. What the labels mean

The pollen tube

Supplement

Supplement: only for the Extended papers (2 and 4). Core students can skip it. What the labels mean

A pollen grain lands on the stigma of a flower of the same species.
A pollen tube grows out of the pollen grain and down through the style.
The pollen tube grows towards the ovary and enters an ovule.
The nucleus of the pollen grain (the male gamete) passes down the tube into the ovule.
The pollen nucleus fuses with the nucleus of the egg cell in the ovule. This is fertilisation, and it forms a zygote.

Supplement

Supplement: only for the Extended papers (2 and 4). Core students can skip it. What the labels mean

You do not need to know how the endosperm is made or how the seed and fruit develop.

Supplement

Supplement: only for the Extended papers (2 and 4). Core students can skip it. What the labels mean

A carpel in section: pollen grains on the stigma, one pollen tube growing down through the style into the ovary and entering the ovule, with the pollen nucleus at the tip of the tube next to the egg cell nucleus. — The **pollen tube** grows down the style and into an ovule. The pollen nucleus fuses with the egg cell nucleus: this is fertilisation.

Common mistake:

Pollination and fertilisation are different. Pollination is the transfer of pollen to the stigma. Fertilisation is the fusion of nuclei.

Written and checked against the Cambridge IGCSE Biology (0610) specification · Updated October 2026

Frequently asked questions

What is the difference between pollination and fertilisation?

Pollination is the transfer of pollen grains from an anther to a stigma, while fertilisation is the fusion of a pollen nucleus with a nucleus in an ovule. Pollination happens first. Only after pollen reaches the stigma can a pollen tube grow down to the ovule, so that the nuclei can fuse.

How are wind-pollinated flowers adapted?

Wind-pollinated flowers have anthers hanging outside the flower on long filaments, so the wind can blow the pollen away. Their stigmas are large and feathery and hang outside, to catch pollen from the air. Petals are small, dull or absent, with no nectar, and they make very large numbers of small, light, smooth pollen grains.

How does a pollen tube grow?

Supplement A pollen tube grows out of a pollen grain after it lands on the stigma of a flower of the same species. The tube grows down through the style towards the ovary and enters an ovule. The pollen nucleus passes down the tube and fuses with the nucleus of the egg cell, which is fertilisation.

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