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Pollination
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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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