Page 18 - Science Coursebook
P. 18
1.6 Fertilisation
The kind of reproduction that happens in flowers is sexual
reproduction.
In sexual reproduction, the nucleus of a male gamete and
the nucleus of a female gamete join together. This is called
fertilisation.
When the nuclei of the two gametes have joined together,
they form a new cell. This cell is called a zygote.
Questions
Think about what you have learnt about sexual
reproduction in humans.
1 What is the name of the male gamete in humans? The yellow spheres are pollen grains of a
2 What is the name of the female gamete in humans? poppy. The orange-red structure is a stigma
3 Where does fertilisation happen in humans? on a poppy flower. You can see tubes
starting to grow from the pollen grains
Fertilisation in a flower (magnifi ed × 3600).
In flowers, the male gamete is a nucleus inside a pollen
grain. The female gamete is a nucleus inside an ovule.
When a flower has been pollinated, there are pollen grains
on its stigma.
The diagram shows how a male nucleus gets from a stigma
to a female gamete.
pollen grain
stigma
ovule
ovary
1 A tube grows out
of a pollen grain
on the stigma.
2 The male gamete
(nucleus) goes
down the tube.
3 The male gamete
fuses with the
female gamete
Fertilisation in a flower. inside an ovule.
16 1 Plants
