Plant Reproduction
Sexual Reproduction in Plants
Link to the Edexcel Syllabus
3.3 Describe the structures of an insect pollinated and a wind
pollinated flower and explain how each is adapted for pollination.
Learning Objectives
• Be able to identify and label the reproductive structures of a
flower, both wind and insect pollinated
• Appreciate the structural adaptations that both wind and insect
pollinated flowers exhibit
• Distinguish between the terms cross and self-pollination and
understand why and how flowers try to prevent self-pollination
Enhancement of learning
• Show an appreciation of the potential impact that the depletion
in honey bee numbers may have on human populations
Flowers are the reproductive organs of plants
Structure and function of the flower
stigma
anther
style
stamen
filament
ovary
ovule
petal
sepal
peduncle
receptacle
carpel
Flower Structure Quiz
• What is the name of the structure labelled X in the diagram?
A.
carpel
B.
sepal
C.
stamen
D.
peduncle
X
Flower Structure Quiz
• Where is pollen made?
A.
stigma
B.
sepal
C.
anther
D.
ovary
Flower Structure Quiz
• Where is the ovule found in a flower?
Flower Structure
Pollination
A.
petals
B.
style
C.
nectary
D.
ovary
Fertilisation
Seed Dispersal
Germination
Test
Flower Structure Quiz
• Which parts of the flower are labelled below:
X
A.
X = style, Y = stigma
B. X = filament, Y = anther
Y
C. X = stigma, Y = style
D. X = anther, Y = filament
Pollination
The pollen grain contains the male sex cell (gamete)
Pollination is the transfer of pollen from the anther to
the stigma
Pollen can be carried between flowers by insects or by
wind
Wind-pollinated flowers are different in structure to insect
pollinated flowers as they do not have to attract insects to
them but do need to be exposed to the wind.
Pollen grains are very
small and light. They
occur in very large
numbers
Anthers are exposed to the
wind so that pollen can easily
be blown away
Stigmas are
feathery to catch
pollen carried in
wind
Petals are small
and green as
there is no need
to attract insects
Flower Structure
No scent or nectary
Pollination
Fertilisation
Seed Dispersal
Germination
Test
Insect-pollinated flowers are adapted to attract insects to
enable the transfer of pollen
Pollen has
barbs for
hooking onto
insect fur
nectar and a
scent present
Anthers positioned
to rub pollen onto
insects
Sticky stigma to
collect pollen
Flower Structure
Pollination
Brightly coloured
petals
Fertilisation
Seed Dispersal
Germination
Test
Pollination can be self pollination or cross-pollination
This is an example of cross-pollination as the pollen travels from one flower to a
different flower.
Self-pollination occurs when pollen falls from the anther onto
the stigma of the same flower
Selfpollination
is not
desirable
as it
reduces
genetic
variation
Flowers will prevent self-pollination by either
having stigma above stamen or…
…by having stamen and stigma mature at different
times.
Pollination Quiz
• Pollination is the transfer from….?
A.
stigma to anther
B.
style to stamen
C.
ovule to filament
D.
anther to stigma
Pollination Quiz
• The two mechanisms for pollination are?
A.
Wind and water
B.
Insect and wind
C.
Insect and water
D.
Wind and birds
Pollination Quiz
• Cross-pollination…
A.
Increases genetic variation
B.
Decreases genetic variation
C.
Is only performed by insects
D.
Is only performed by wind
Pollination Quiz
• Flowers are adapted for wind-pollination by…
A.
Having bright petals and a scent
B.
Having a nectary
C.
Having feathery stigmas
D.
Having sticky stigmas