Seed Dispersal

involves methods and types of dispersal

1. SEED SEED
DISPERSALDISPERSAL

2. NEED FOR DISPERSALNEED FOR DISPERSAL
To spread out and grow in To spread out and grow in
new places.new places.
To get sufficient space, light, To get sufficient space, light,
and nutrients for and nutrients for
propagation.propagation.
Evolution of species.Evolution of species.

3. HOW IT WORKS?HOW IT WORKS?
Seeds lacks power of Seeds lacks power of
locomotion so are locomotion so are
dependant on external dependant on external
agencies for dispersal.agencies for dispersal.

4. :-
AGENCIESINVOLVED
:-
AGENCIESINVOLVED
Two broad categories are:-Two broad categories are:-
BY PLANT ITSELF BY PLANT ITSELF
BY EXTERNAL AGENCIES BY EXTERNAL AGENCIES

5. BY PLANT ITSELF BY PLANT ITSELF
{autochory}{autochory}
Plants disperse their seeds on their Plants disperse their seeds on their
own.own.
They disperse seeds by bursting with They disperse seeds by bursting with
a sudden jerk.a sudden jerk.
Loud sounds can be produced too Loud sounds can be produced too
during their dehiscence.during their dehiscence.
The process may also be termed as The process may also be termed as
“EXPLOSIVE MECHANISM”“EXPLOSIVE MECHANISM”

6. MAIN EXAMPLES OF MAIN EXAMPLES OF
AUTOCHORY:-AUTOCHORY:-
•DRY PODS OF DRY PODS OF
FAMILY FAMILY
LEGUMINOSEAE LEGUMINOSEAE
(PEA, BEAN) (PEA, BEAN)
FIRST BREAKS FIRST BREAKS
INTO TWO INTO TWO
HALVES.HALVES.

7. THEN THESE HALVES THEN THESE HALVES
TWIST SPIRALLY TO TWIST SPIRALLY TO
THROW SEEDS TO THROW SEEDS TO
LONG DISTANCESLONG DISTANCES
THE TWO HALVES THE TWO HALVES
CURLS BACK ND FLICK CURLS BACK ND FLICK
OUT THE SEEDS IN AN OUT THE SEEDS IN AN
EXPLOSIVE MANNER.EXPLOSIVE MANNER.
(COMPARE THE CURLED POD (COMPARE THE CURLED POD
WITH THE ENTIRE ONE)WITH THE ENTIRE ONE)

8. EXAMPLE 2ndEXAMPLE 2nd
GORSE IS A GOOD GORSE IS A GOOD
EXAMPLE.EXAMPLE.
IN SUMMERS THE IN SUMMERS THE
EXPLODING PODS EXPLODING PODS
SOUNDS ALMOST SOUNDS ALMOST
LIKE GUN SHOTS.LIKE GUN SHOTS.
SMALL SEEDS ARE SMALL SEEDS ARE
THROWN VERY THROWN VERY
EFFECTIVELY FROM EFFECTIVELY FROM
IMMEDIATE AREA.IMMEDIATE AREA.

9. THE EXTERNAL
AGENCIES
ANEMOCHORY
( )
BY AIR
HYDROCHORY
( )
BY WATER
ZOOCHORY
( )
BY ANIMALS

10. ANEMOCHORY:-ANEMOCHORY:-
MAIN CHARACTERISTICS :-MAIN CHARACTERISTICS :-
2.2.SEEDS ARE DISPERSED BY THE SEEDS ARE DISPERSED BY THE
AGENCY OF WIND.AGENCY OF WIND.
3.3.SEEDS MUST BE LIGHT ND SMALL.SEEDS MUST BE LIGHT ND SMALL.
4.4.THEY MAY ADOPT DIFFERENT THEY MAY ADOPT DIFFERENT
ADAPTATIONS LIKE OUTGROWTHS, ADAPTATIONS LIKE OUTGROWTHS,
HAIRS, WINGS etc… WHICH HAIRS, WINGS etc… WHICH
INCREASE THEIR SURFACE AREA TO INCREASE THEIR SURFACE AREA TO
FLY IN WIND FOR LONGER.FLY IN WIND FOR LONGER.

11. MAIN EXAMPLES :-MAIN EXAMPLES :-
•““PEPPER POT PEPPER POT
TYPE”TYPE”
The flower ovary The flower ovary
contains the seeds contains the seeds
.It becomes dry and .It becomes dry and
disperses the seeds disperses the seeds
when shaken by when shaken by
windwind

12. 2. “PARACHUTE2. “PARACHUTE TYPETYPE””
•FEATHERY HAIRS FEATHERY HAIRS
HELPS THEM TO HELPS THEM TO
FLOAT ON WIND FLOAT ON WIND
FOR LONG TIME.FOR LONG TIME.

13. MORE TYPES MAY BE:-MORE TYPES MAY BE:-
WINGED SEEDSWINGED SEEDS COTTON GRASSCOTTON GRASS

14. HYDROCHORY:-HYDROCHORY:-
MAIN CHARACTERISTICS MAIN CHARACTERISTICS
ARE:-ARE:-
PLANTS GROWING NEAR PLANTS GROWING NEAR
WATER DISPERSES SEEDS WATER DISPERSES SEEDS
THROUGH WATER.THROUGH WATER.
SOME KIND OF FLOATING SOME KIND OF FLOATING
DEVICES ARE ALSO DEVICES ARE ALSO
FORMED LIKE FORMED LIKE FIBROUS FIBROUS
MESOCARP IN COCONUT, MESOCARP IN COCONUT,

EMBEDDING OF SEEDS IN EMBEDDING OF SEEDS IN
LONG THALAMUS IN CASE LONG THALAMUS IN CASE
OF LOTUS OR SMALL, LIGHT OF LOTUS OR SMALL, LIGHT
AND AIR FILLED SEEDS IN AND AIR FILLED SEEDS IN
LILLY LILLY etc….etc….

15. 1. “POND IRIS”1. “POND IRIS”
•THE SEED POD THE SEED POD
BREAKS OPEN WHEN BREAKS OPEN WHEN
THEY RIPEN WITH A THEY RIPEN WITH A
FORCE.FORCE.
•BEING LOCATED BEING LOCATED
NEAR WATER THOSE NEAR WATER THOSE
SEEDS THAT FALL IN SEEDS THAT FALL IN
WATER FLOWS AWAY WATER FLOWS AWAY
THROUGH LONG THROUGH LONG
DISTANCES.DISTANCES.

16. ZOOCHORY:-ZOOCHORY:-
MAIN CHARACTERISTICS MAIN CHARACTERISTICS
ARE:-ARE:-
2.2.THE SEEDS ARE LIGHT THE SEEDS ARE LIGHT
AND ARE STICKY OR AND ARE STICKY OR
PROVIDED WITH HOOKS PROVIDED WITH HOOKS
3.3.SOME PLANTS PRODUCE SOME PLANTS PRODUCE
FLESHY EDIBLE FRUITS FLESHY EDIBLE FRUITS
THAT ARE DISPERSED THAT ARE DISPERSED
THROUGH THE WASTES THROUGH THE WASTES
EXCREATED BY THE EXCREATED BY THE
ANIMALS.ANIMALS.
4.4.HUMAN TRAVELLERS HUMAN TRAVELLERS
ALSO CARRY SOME ALSO CARRY SOME
SEEDS WITH THEM.SEEDS WITH THEM.

17. 1. “BURDOCK SEED HEAD”1. “BURDOCK SEED HEAD”
AS SHOWN THESE AS SHOWN THESE
SEEDS OF THE SEEDS OF THE
PLANTS HAVE PLANTS HAVE
HOOKS ON THEIR HOOKS ON THEIR
SURFACE.SURFACE.
THESE ARE THESE ARE
EDHERED TO FUR EDHERED TO FUR
OF MAMMALS AND OF MAMMALS AND
ARE SPREAD .ARE SPREAD .

18. 2. “THE BERRIES”2. “THE BERRIES”
THE BERRIES ARE EATEN THE BERRIES ARE EATEN
BY THE BIRDS SUCH AS BY THE BIRDS SUCH AS
BLACKBIRDS AND PIGEONS. BLACKBIRDS AND PIGEONS.
MICE, DEER AND EVEN MICE, DEER AND EVEN
FOXES ALSO EAT THEM.FOXES ALSO EAT THEM.
THE SMALL HARD SEED IS THE SMALL HARD SEED IS
HIDDEN INSIDE THE FRUIT HIDDEN INSIDE THE FRUIT
THAT PASSES INTO THE THAT PASSES INTO THE
GUT OF THE OF THE GUT OF THE OF THE
ANIMAL.ANIMAL.
THE SEED REMAINS THE SEED REMAINS
UNDIGESTED AND IS UNDIGESTED AND IS
EXCREATED OUT AS SUCH EXCREATED OUT AS SUCH
AND IS DISPERSED.AND IS DISPERSED.

19. THANKS FOR YOUR THANKS FOR YOUR
PATIENCEPATIENCE