Attracts insects for
pollination (in insect
pollinated plants)
Sepal
Protects the plant
whilst it is in a bud
Nectary
Produces sugary nectar that attracts insects
for pollination (in insect pollinated plants)
Pollination
Self pollination
When pollen of the same plant
begins fertilisation with the stigma
of the same plant, this is avoided by
different maturing times, or by
position of the anther to the stigma
Cross pollination
When pollen from one plant reaches
the stigma of another plant, this is
prefered as it increases variation
Insect Pollination
Insect used to spread
pollen for anther of one
plant to stigma of another
Large, bright
flowers
Scented
Nectar
Large, rough, but just a
little amount of pollen
Anther and stigma inside flower
so that insect touches them
Wind Polination
Wind used to disperse
pollen from one anther to
another stigma
No nectar or scent
Small, green petals
Lots of light pollen
Feathery anthers and
stigmas out of the flower to
catch and release pollen
Fertilisation
A pollen tube grows from the pollen
landing onto the stigma and grows
down the style, into the ovary
There are 8 haploid nuclei in the ovary including
the egg cell and 2 nuclei in the central cell
One male nucleus fuses with the
two nuclei from the central cell to
form a triploid endosperm cell
The endosperm develops into a
food store for the seedling
One male nucleus fuses with the
egg cell to form a diploid zygote
The ovule develops into a seed
The zygote becomes the plant embryo
Seeds
Dispersal
Animal
Seeds dispersed in fruit
eaten by animal, then
planted elsewhere
Wind
Seeds have wings
and glide elsewhere
in the wind
Mechanical
Seeds in pods that
burst open, sending
the seed elsewhere
Water
Buoyant seeds
travel on water
Germination
When the conditons
are correct, the seedling
will begin to grow