Agents of Pollination

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Pollination in Plants
PRESENTED BY Gurmehar Kaur
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Agents of Cross-Pollination

• A pollinator is any agent that transfers pollen
  from male to female reproductive parts of flowers
  of the same plant species.
• The two commonest agents of cross-pollination are
  insects and wind. But, some flowers are also
  pollinated by certain animals and birds, like
  squirrels, bats, etc., or even by water in the
  case of some aquatic plants. Each category has
  some special features to promote changes of
  pollination.

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Pollination Agents
Biotic factor
Abiotic factor
Birds
Wind
Insects
Bats
Water
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Wind Pollination

• Wind Pollination. Wind pollination (also called
  'Anemophily') describes the process of the
  transfer of pollen from one individual plant to
  another, whereby the pollen is carried by air
  currents. Plants may be non-flowering common in
  grasses and grains, or flower-producing.

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Wind pollinated flowers usually posses the
following special features

• The flowers are small.
• They are usually not brightly coloured and often
  dull green.
• They do not produce scent or nectar.
• The stamens are long and hang out of the flower
  to be exposed to air.
• The anthers are large and loosely attached to the
  filaments so that the slightest wind may move
  them.
• Pollen is produced in very large quantities.
• Pollen grains are light, dry and smooth so that
  they can easily be carried away by wind.
• The stigma are feathery and hang out of the
  flower to tap the pollen grains.

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Examples of Wind Pollinated PLANTS

• Wheat

Grasses
Catkins
Maize
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Insect pollination

• Many insects visit flowers for nectar. During the
  process some pollen sticks to the body parts of
  these insects and when this insect visits another
  flower the pollen grains are brushed off, some of
  which fall on the stigma and thus pollination
  takes place.
• Hence we conclude that insect pollination is a
  type of pollination in which the pollen is
  transferred from one insect to another by
  insects.
• Its estimated that over 84 of crops in Europe
  are dependent upon insect pollination.

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Insect pollinated flowers usually posses the
following special features

• The flowers are large.
• They are usually brightly coloured to attract
  insects.
• They usually emit scent for attracting insects.
• They produce nectar which is food for the
  insects.
• The pollen grains are sticky or spiny to enable
  them to be carried by insects easily.
• The stigma is sticky and does not generally hang
  out from the flower.

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Examples of Insect Pollinated plants

• Lobelia siphilitica

Lemon Bee Balm
Common Evening Primrose
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Water pollination

• Pollination in aquatic plants is usually carried
  out by water. Water pollinated flowers release
  there pollen grains into the water and are
  passively carried to other plants by water
  currents.

(b)
(a)
These male (a) and female (b) catkins from the
goat willow tree (Salix caprea) have structures
that are light and feathery to better disperse
and catch the wind-blown pollen.
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Water pollinated flowers usually posses the
following special features

• Pollen grains are produced in large numbers.
• In some plants the pollen grains have a specific
  gravity almost equal to that of water so that
  they remain floating below the surface of water.
• In some special cases male flowers are such that
  they float on the surface of water till they meet
  female flowers e.g. Vallisneria.

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Examples of Water Pollinated plants

• Eel-grass

Hydrilla
Coontail
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Something More

• Some flowers are pollinated by birds
  (ornithophily, ornitho bird), e.g. Bignonia,
  canna
• Elephophily is the pollination affected by
  elephants. Elephophily is found in Rafflesia
  whose flowers are very large and are found at
  ground level. The pollen grains of one flower get
  attached to the feet of elephants and may be
  carried to the stigma of another flower when
  trampled by those feet.

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