reproduction in flowering plants
TRANSCRIPT
REPRODUCTION IN
FLOWERING PLANTS
The Parts of a Flower
In a typical flower, there are four main parts:
Petals, sepals, stamen and carpel.
There are two main types of flower:
Insect- pollinated flowers
Wind- pollinated flowers
CHAPTER 2
REPRODUCTION IN FLOWERING PLANTS
THE FLOWER STRUCTURE
stigma
style
ovary
ovule
carpel
anther
filament
stamen
petal
sepal
receptaclepeduncle
Flower Structure Pollination Fruit Development Seed Dispersal Germination Test
• What is the name of the structure labelled X in the diagram?
sepal
stamen
peduncle
carpel
X
FLOWER STRUCTURE QUIZ• Where is pollen made?
stigma
sepal
anther
ovary
FLOWER STRUCTURE QUIZ• Where is the ovule found in a flower?
petals
style
nectary
ovary
Flower Structure Pollination Fertilisation Seed Dispersal Germination Test
• Which parts of the flower are labelled below:
X = filament, Y = anther
X
YX = stigma, Y = style
X = anther, Y = filament
X = style, Y = stigma
Flower Structure Pollination Fertilisation Seed Dispersal Germination Test
1. Petals (corolla): often with bright color, pattern
and scent to attract insects and birds.
2. Carpels(female gametes):
Stigma :sticky surface that collects pollen
Style : a neck that joins the stigma to the ovary
Ovary : part of the ovary that produces ovules
3. Stamen (male gametes):
anther :head of the stamen that contain pollens grain
Filament : long stalk to supports the anther
4. Sepals ( calyx): leaves that protect the young flower
buds
Pollen can be transported from the anther
to the stigma by insects, birds
or other animals, wind and water,
INSECT-POLLINATED FLOWERS ARE ADAPTED TO
ATTRACT INSECTS TO THEM TO ENABLE TRANSFER
OF POLLEN
Sticky stigma to
collect pollenBrightly coloured
petals
nectar and a scent
present
Pollen has
barbs for
hooking onto
insect fur
Anthers positioned to
rub pollen onto insects
WIND-POLLINATED FLOWERS ARE DIFFERENT IN
STRUCTURE BECAUSE THEY DO NOT HAVE TO
ATTRACT INSECTS TO THEM BUT DO NEED TO BE
EXPOSED TO THE WIND.
Petals are small and
green as there is no
need to attract insects
Stigma are feathery
to catch pollen
carried on wind
Anthers are exposed to the wind
so that pollen can easily be
blown away
Pollen grains are very small
and light. They occur in very
large numbers
No scent or nectary
Self-Pollination and Cross-pollination
Self –pollination: if the pollen goes from an anther to the
stigma of the same flower or other flowers on the same
plant.
Cross-Pollination: it the pollen goes from an anther to
stigma of a flower on other plant of the same species.
SELF-POLLINATION OCCURS WHEN POLLEN FALLS
FROM THE ANTHER ONTO THE STIGMA OF THE
SAME FLOWER
• Self-pollination is not desirable as it reduces variation
• Click to show animation of self-pollination
Flower Structure Pollination Fertilisation Seed Dispersal Germination Test
POLLINATION QUIZ
• Pollination is the transfer from….?
the stigma to anther
style to stamen
anther to stigma
ovule to filament
POLLINATION QUIZ
• The two mechanisms for pollination are?
Wind and water
Insect and water
Insect and wind
Wind and birds
POLLINATION QUIZ
• Cross-pollination…
Increases variation
Decreases variation
Is only performed by wind
Is only performed by insects
POLLINATION QUIZ
• Flowers are adapted for wind-pollination by…
Having feathery stigmas
Having a nectary
Having bright petals and a scent
Having sticky stigmas
Fertilisation
When a pollen grain reaches the stigma, a small tube forms
and grows down into the ovary. The pollen cells travel down
this tube until they reach the ovary.
When a male pollen cell reaches the ovary, it joins with a
female ovule to fertilise it.
ONCE POLLINATION OCCURS A TUBE GROWS
FROM THE POLLEN GRAIN DOWN THROUGH THE
STYLE TO THE OVULE
Flower Structure Pollination Fruit Development Seed Dispersal Germination Test
stigma
style
ovary
ovule
carpel
Note: Petals not shown in order to
simplify diagram
Click to view the
animation
FERTILISATION OCCURS WHEN THE MALE GAMETE
FUSES WITH THE OVULE (THE FEMALE GAMETE)
Complete the
fertilisation section
of the worksheet
(you will need to
refer to your text
book)
Flower Structure Pollination Fruit Development Seed Dispersal Germination Test
Click to view the
animation
Dispersing the fruits and seeds
A plant produce many fruits. If they were all fall to
the ground around their parent, they would
compete with each other for light, water and
minerals in the soil, and so many would die.
Over crowding is prevented by fruit and seed
dispersal.
SEEDS NEED TO BE DISPERSED AWAY FROM THE
PARENT PLANT IN ORDER TO REDUCE COMPETITION
FOR SPACE, LIGHT, NUTRIENTS AND WATER.
• Seeds can be dispersed by:
• Wind
• Water
• Mechanical
• Animals