1. NAME : ROHINI KANBARKAR
CLASS: BSc 3 SEM. (B)
SUBJECT : BOTANY
GUIDED BY : MRS. POOJA
MELVANKI
2.
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 .
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
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 .
13.
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
