The tube to the ovule

The idea

On a compatible stigma, pollen grains grow pollen tubes down the style into the ovary; the male gamete travels through the tube and fuses with the egg cell in the ovule, forming a zygote that becomes an embryo.

A long way down

Pollen lands on the stigma at the top of the pistil. The egg cell is far below it, inside the ovary.

How do you think the male gamete reaches the egg cell?

• Through a tube that the pollen grain grows
• It floats through the air inside the flower
• It is carried by the roots

Down the style

Press Next step to follow the pollen grain.

Fertilisation

The pollen grain made a tube through the style. The male gamete travelled down it and fused with the egg cell. That fusion is fertilisation, and it is the beginning of a new life.

On a compatible stigma, pollen grains grow pollen tubes down the style into the ovary. The male gamete travels through the tube and fuses with the egg cell in the ovule, forming a zygote that becomes an embryo.

Notes

The pollen tube carries the male gamete to the ovule, where it fuses with the egg cell (fertilisation). The zygote becomes an embryo.

Check yourself

What does a pollen grain grow on a compatible stigma?

The pollen tube grows down through the style into the…

The male gamete fuses with the egg cell in the…

The fertilised egg is called a…

• A fruit. A fruit forms from the ovary after fertilisation.
• A petal. Petals are coloured projections of the flower, not formed by a pollen grain.
• A pollen tube — correct. Yes!
• ovary — correct. Yes!
• anther. The anther is part of the stamen, where pollen is made.
• sepal. Sepals are the green covering of the flower, not part of the pistil.
• stigma. The stigma is where the pollen lands. The egg cell is in the ovule.
• ovule — correct. Yes!
• filament. The filament is part of the stamen.
• spore. A spore is formed by moulds.
• pollen grain. A pollen grain carries male gametes. The fertilised egg is the zygote.
• zygote — correct. Yes!