The document defines seed dispersal as the movement of seeds away from their parent plant and outlines its importance in reducing competition and increasing progeny variety. It describes various methods of seed dispersal including by wind (anemochory), water (hydrochory), animals (zoochory), and explosive mechanisms (autochory). Each method has specific characteristics and examples that illustrate how seeds can travel long distances and establish in new environments.

1. NAME : ROHINI KANBARKAR
CLASS: BSc 3 SEM. (B)
SUBJECT : BOTANY
GUIDED BY : MRS. POOJA
MELVANKI

3. DEFINITION :
•Seed dispersal means the dissemination of seeds
to various distances from their parent plant .
OR
•Seed dispersal is the movement, spread or
transport of seeds away from the parent plant.

4. Reasons for seed dispersal
• If numerous seeds fall and germinate right beneath
the parent plant ,they have to compete for light, water
and nutrients from the soil.
• Group of seeds can be easily detected and destroyed
by the animals .
• Increase chances of back – crossing , consequently
poor progeny .

5. Importance of seed dispersal
• Decrease the competition between the parent plant and the
seeds.
• It decrease overcrowding so avoids competition for
environment, light, space and nutrients
• Reduces the amount of seeds lost due to predation
• Increase variety in progeny .

6. SEED DISPERSAL
BY WIND BY WATER BY ANIMALS
BY
EXPLOSION

7. SEED DISPERSAL BY WIND : ANEMOCHORY
• Some seeds are carried to the new place by the means
of wind .
• Seeds from plants like dandelions and cottonwood trees
are light and have feathery bristles and can be carried
long distances by the wind.
• Some plants, like kauri and maple trees, have ‘winged’
seeds.
• Needs large number of seed production .
• Presence of wings, hairs and light weight

8. Dandelions : hairy parachutes
maple : winged seeds
cotton seed : hairy parachutes

9. Orchids
• Produces about 700 million seeds per plant.
• DUST SEEDS ( tiny seeds)

10. Water dispersal : HYDROCHORY
• Seeds of plants which grows near water bodies such as beach , river
etc. use water as a means of dispersal.
• The seeds float away from the parent plant when fall into the water.
• Example, water lily , coconut
• Have special devices to prevent the water penetration which helps in
floating for long period of time and distance .

11. Coconut
• Coconuts can travel thousands of kilometers to reach the away from the place
they started and still germinate .
• Smooth and waterproof epicarp.
• Original home of coconut is said to be MALAYSIA.

12. Animal dispersal : ZOOCHORY
1. BY EATING THE FRUITS : Animals like birds commonly eat
the fruit bearing seed .
only juicy part is digested and seed travels through the
digestive system of bird then is excreted out to develop in new
plant at new place .
2. EXTERNALLY CARRIED BY ANIMALS : Seeds sticks to the
body surface of animals or held in their mouth .

14. EXPLOSIVE DISPERSAL : AUTOCHORY
• Presence of pods which explodes when seed ripe resulting in violent
ejection of seeds at far distances.
• Example, viola, peas , gorse and beans have seedpods that dry out once
the seeds are ripe. When dry, the pods split open and the seeds scatter.
• Gorse : popping pods of seeds , in summer

15. Arceuthobium : explosive seed

16. THANK-YOU