Sexual reproduction in plants for Class X

2. Overview of floral organs

3. Structure of the flower
• It is the organ for sexual reproduction
• It has sepals petals , stamens & carpels
• Stamens & carpels are the reproductive parts of
the flower which contain the germ cells
Carpel/

4. Flowers are of two types
1. Unisexual flowers
2. Bisexual flowers

5. Unisexual flowers
Flower which contains either stamen or
pistil is called unisexual flower
Ex-papaya , water melon

6. Flower which
contains both stamen
& pistil is called
Bisexual flower
EX- Hibiscus ,
Mustard

7. Reproductive floral organs:
female• Carpel or pistil – female
reproductive organ
• Itcontains:
• Ovary – enlarged structure
at the base of carpel/pistil
where the ovules are
located; it will become the
fruit after fertilization
• Ovules – contains female
germ cell or egg cell.
• It becomes
seed after fertilization
• Stigma – is where pollen
sticks to
• Style – is the long tube
that connects stigma to
ovary
carpel
or
pistil
ovary

8. Reproductive floral organs: male
• Stamen – male floral organ
• It consists of:
• Anther – part of the stamen that produces pollen
• Filament – stalk-like structure that holds anther
• Pollen grain –male gametophyte which consist
of male gametes

9. Steps in sexual reproduction
• 1. Pollination
• 2. Germination of pollen grain
• 3. Fertilization
• 4. Formation of the fruit & seed

10. POLLINATION
• The transfer of
pollen from the male
anther to the female
stigma

11. NEED FOR POLLINATION
• The male gamete
present in the pollen
grain fuses with the
egg cell present in
the ovule to form the
zygote which
produces a new plant
• For this the pollen
needs to be
transferred from
stamen to the stigma

12. Types of pollination
• 1. Self pollination
• 2. Cross pollination

13. Transfer of pollen
grains from anther to
the stigma of the same
flower is called self
pollination

14. Transfer of pollen grains from anther to the
stigma of the another flower is called cross
pollination

16. Pollen grain germination
• After the pollen lands on
the suitable stigma, it
has to reach the female
gamete present in the in
the ovary
• For this pollen grain
germinates on the
stigma & forms a pollen
tube
• It travels through the
style & reaches the ovule
present in the ovary

17. Fusion of the male &
female gametes is
called fertilization
It occurs inside the
ovule

18. Pollen grain germination & fertilization

19. FORMATION OF THE FRUIT &
SEED
• After fertilization the zygote devides
several times to form an embryo within
the ovule
• The ovule develops a tough coat & is
gradually converted into a seed
• The ovary grows rapidly to form a fruit
• Sepals , petals, stigma, style fall down

20. Double Fertilization
• Double fertilization occurs: One sperm
nucleus (1n) fertilizes the egg, producing a
zygote (2n)  which becomes the plant
embryo inside the seed
• Another sperm nucleus fuses with the polar
nuclei, resulting in a triploid endosperm (3n)
• Endosperm is a source of food for the young
embryo.
Endosperm

22. Structure of the seed
•It has cotyledons
•Plumle- which gives shoot
system
•Radicle which gives root
system

23. Seed germination
• The seed
contains the
future plant or
embryo which
develops into
seedling under
appropriate
conditions. This
process is called
seed germination