4.9 Pollination

8/13/2019 4.9 Pollination

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Pollination
http://www.youtube.com/watch?v=V5yya4elRLwhttp://www.youtube.com/watch?v=V5yya4elRLw


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4.9 Pollination Pollinationis the process of transferring ripe pollen from

the anther to stigma.

There are two type of pollination :

1) Self-pollinationtake place when the pollen from theanther of a flower is transferred to thestigmaof thesame floweror another floweron the same plant.

Polentransferredto stigma of

same flower

stigma

Pollen transferredto another flowerof same plant

anther

stigma

anther


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2) Cross-pollination- the transfer of pollen of a flower to thestigma of another floweron different plantof the samespecies.

anther

pollen

stigma


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Table 4.9.1 Comparison between sel-pollination and cross pollination

Self-pollination Cross-pollination

Involves only one plant Involves two plants of the same

species

Requires one or two flowers fromthe same plant

Requires two flowers from thedifferent plant of the samespecies

If it involves one flower, both the

anther and stigma must mature atthe same time. If it involves twoflowers, the anther and stigmacan mature at different times

The anther and stigma can mature

at different times

Less variety in new plants More variety in new plants


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4.9.1 Pollinating agents Agents of pollination include organisms or media that

transfer the pollen grains from the anther to thestigma of a flower.

1. Wind Is a pollinating agent for most monocotyledonous

plant, like maize, grass and paddy. Wind-pollinated flowers usually :

white or light in colour, small, have no smell and nonectar. Have long filaments to expose the pollen to wind. Produce plentyof small, light and smooth pollen. The styles and stigma are long. The stigma is

featheryto trap the pollen carried by the wind.


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1. Insects (bees, butterflies) Attracted by big, colourful andscented flowers.

When insect lands on the flower to suck nectar forfood, pollen sticks to the hairy legs and body ofinsect.

When insect lands on another flower to collect food,the pollen may drop off and stick on the stigma of

that flower. Insect-pollinated flowers :

Produce small amounts of pollen.

Such pollen is big, sticky, heavy and rough.

Their style are short and the stigma has sticky

surface.


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2. Animals(birds, bats)

Pollinate flower when they suck nectar from theflowers.

Such flowers are usually big, colourful, scented, andproduce rough and sticky pollen.

The pollen sticks to the beak or body of the

animals. When animals such a bird sucks out nectar with its

long and pointed beak, pollen sticks to the beak.


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3. Watero Is a pollinating agent for water

plantslike Elodeaand Hydrilla.

o The flower floats on water surface.

o The water carries the pollen from the

pollen from the anther to the stigma.


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Table 4.8 Comparison between wind and insect pollinated flowers

Wind-pollinated flower Insect-pollination flower

Small, pale coloured, not scented,no nectar

Big, brightly coloured, scented,nectar present

Long filament with big anther atthe end, filament sways in thewind and pollen disperses

Short filament and small anther atthe end

Plenty of small, light and smoothpollen

Big, rough, sticky and less amountof pollen

Long style Short style

Long and feathery stigma Short and sticky stigma


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The Advantage Of Cross-pollination

New varitiesof plants

Healthier plants which can adapt better

to changes in invironment Healthier seeds

New plants that are more resistant to

pest and diseases


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Use Of Cross-pollination In Agriculture

Human act as pollinating agent; widely used in thefield of agriculture to produce better and

higher quality crops. In Malysia, the various agricultural agencies like

the Malayan Agriculture Research andDevelopment Institute (MARDI) and the alaysianPalm Oil Bord (MPOB) are responsible forcarrying out research to increase the quantityand quality of agricultural products.

Among the new crop plants produce by cross-pollination are oil palm, maize plants and papaya

plants.


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Thank You!

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4.9 Pollination