SEED SEED DISPERSALDISPERSAL

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.

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.

AGENCIES INVOLVED:-AGENCIES INVOLVED:-

Two broad categories Two broad categories are:-are:-

1.1. BY PLANT ITSELF BY PLANT ITSELF

2.2. BY EXTERNAL AGENCIES BY EXTERNAL AGENCIES

BY PLANT ITSELF BY PLANT ITSELF {autochory}{autochory}

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

MAIN EXAMPLES OF MAIN EXAMPLES OF AUTOCHORY:-AUTOCHORY:-

1.1. DRY PODS OF DRY PODS OF FAMILY FAMILY LEGUMINOSEAE LEGUMINOSEAE (PEA, BEAN) (PEA, BEAN) FIRST BREAKS FIRST BREAKS INTO TWO INTO TWO HALVES.HALVES.

THEN THESE HALVES THEN THESE HALVES TWIST SPIRALLY TO TWIST SPIRALLY TO THROW SEEDS TO THROW SEEDS TO LONG DISTANCESLONG DISTANCESTHE 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)

EXAMPLE 2ndEXAMPLE 2ndGORSE 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.

THE EXTERNALAGENCIES

ANEMOCHORY(BY AIR)

HYDROCHORY(BY WATER)

ZOOCHORY(BY ANIMALS)

ANEMOCHORY:-ANEMOCHORY:-MAIN CHARACTERISTICS :-MAIN CHARACTERISTICS :-

1.1. SEEDS ARE DISPERSED BY THE SEEDS ARE DISPERSED BY THE AGENCY OF WIND.AGENCY OF WIND.

2.2. SEEDS MUST BE LIGHT ND SMALL.SEEDS MUST BE LIGHT ND SMALL.3.3. 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.

MAIN EXAMPLES :-MAIN EXAMPLES :-1.1. ““PEPPER POT PEPPER POT

TYPE”TYPE”The flower ovary The flower ovary contains the contains the seeds .It becomes seeds .It becomes dry and disperses dry and disperses the seeds when the seeds when shaken by windshaken by wind

2. “PARACHUTE2. “PARACHUTE TYPETYPE””

1.1. FEATHERY HAIRS FEATHERY HAIRS HELPS THEM TO HELPS THEM TO FLOAT ON WIND FLOAT ON WIND FOR LONG TIME.FOR LONG TIME.

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

HYDROCHORY:-HYDROCHORY:-MAIN CHARACTERISTICS ARE:-MAIN CHARACTERISTICS ARE:-

1.1. PLANTS GROWING NEAR WATER PLANTS GROWING NEAR WATER DISPERSES SEEDS THROUGH DISPERSES SEEDS THROUGH WATER.WATER.

2.2. SOME KIND OF FLOATING SOME KIND OF FLOATING DEVICES ARE ALSO FORMED DEVICES ARE ALSO FORMED LIKE LIKE FIBROUS MESOCARP IN FIBROUS MESOCARP IN COCONUT, COCONUT, EMBEDDING OF EMBEDDING OF SEEDS IN LONG THALAMUS IN SEEDS IN LONG THALAMUS IN CASE OF LOTUS OR SMALL, CASE OF LOTUS OR SMALL, LIGHT AND AIR FILLED SEEDS IN LIGHT AND AIR FILLED SEEDS IN LILLY LILLY etc….etc….

1. “POND IRIS”1. “POND IRIS”

1.1. THE SEED POD THE SEED POD BREAKS OPEN WHEN BREAKS OPEN WHEN THEY RIPEN WITH A THEY RIPEN WITH A FORCE.FORCE.

2.2. 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.

ZOOCHORY:-ZOOCHORY:-MAIN CHARACTERISTICS MAIN CHARACTERISTICS ARE:-ARE:-

1.1. THE SEEDS ARE LIGHT THE SEEDS ARE LIGHT AND ARE STICKY OR AND ARE STICKY OR PROVIDED WITH HOOKS PROVIDED WITH HOOKS

2.2. 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.

3.3. HUMAN TRAVELLERS HUMAN TRAVELLERS ALSO CARRY SOME ALSO CARRY SOME SEEDS WITH THEM.SEEDS WITH THEM.

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 .

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 BLACKBIRDS AND PIGEONS. MICE, DEER AND PIGEONS. MICE, DEER AND EVEN FOXES ALSO EAT EVEN FOXES ALSO EAT THEM.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.

THANKS FOR YOUR THANKS FOR YOUR PATIENCEPATIENCE