Pollination.

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Department of Botany JES.College, Jalna
By
Mr. Yogesh Urdukhe
Department of Botany JES College Jalna

Structure of flower
 Flower is modified shoot
 To attract pollinators with colorful petals, scent,
nectar and pollen
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Reproductive floral organs: female
Carpel or pistil – female reproductive organs
Stigma – is where pollen sticks to
Style – is the long tube that connects stigma to ovary
Ovary – enlarged structure at the base of carpel/pistil where the ovules are located;
it will become the fruit.
Ovules – contains female
gametophyte, becomes
the seed
carpel
or
pistil
ovary
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Reproductive floral organs: male
 Stamen – male floral organ, consists of:
 Anther – part of the stamen that produces pollen
 Filament – stalk-like structure that holds anther
 Pollen – immature male gametophyte
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Non-reproductive floral organs
 Petals – whorl of flower organs that are often brightly colored to attract
pollinators
 Corolla – whorl of petals in a flower
 Sepals – whorl of leaf-like organs outside the corolla; help protect the
unopened flower bud.
 Calyx – whorl of sepals in a flower
 Tepals – when sepals and petals look the same
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Transfer of pollen from anther to stigma
Pollination
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Why is pollination important?
 Sexual reproduction is important for evolution:
 Sexual reproduction produces variable offspring,
creating diversity and variation among populations
(shuffling of genes)
 You need variation for Natural Selection to occur
 Sexual reproduction is advantageous to an organism
only if it happens with someone other than itself!
 Outbreeding = good! (inbreeding = bad…)
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Types of pollination
 Self pollination (Autogamy)
 Cross pollination
 Geitoanogamy : Pollination has occurred between two flower on the
same plant
 Xenogamy : Pollination has occurred between two flower on the
different plant
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Mechanism for Self-polliation
 Bisexual flower
 The flower which achieve anther dehiscence and receptive stigma
simultaneously
 Cleistogamy :- Commelina benghalensis ,
 In family Malvaceae the androecium is monoadulphous having
staminal column and the capited stigma project beyond the staminal
column
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Mechanism Cross pollination
 Self sterility – Inabilaty of pollen to germinate on it’s own stigma
 Dichogamy - The maturation time of male and female is different
 Herkogamy – Structure of male and female sex organs itself proves a
barrier to self-pollination. Stigma projects beyond the stamen
(Caryophyllus) or anther dehisce at a distance from its own stigma
(Gloriosa ) , pollene remain aggregated in pollinia (Orchids)
 Heterostyly - Difference in the length of style and the length of stamen
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Vector / Agencies
Anemophily: Transfer of pollen by wind
Adaptation in male flower
 Plant bears small and inconspicuous flower
 Perianthe lobes absent
 Pollene grains are small, light , smooth and dry
Adaptation in female flower
 Stigma must be large and feathery , brush like
 It having considerable area to catch the pollen
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Hydrophily :
Transfer of pollen by water
 Hypohydrophily – it includes plants which are pollinated in side the water
eg.- Ceratophyllum, Najas and zostera .
 Epihydrophily - it includes plants which are pollinated on the surface of the water
eg.- Vallisneria spiralis
Entomophily :
Transfer of pollen by water i.e. Bees, Flies, Waps, Moths and Betles
 Bees contributes up to 80% of all pollination done by insect
 Brightly coloured
 Sweet fragrance or unpleasant smell
 Produce Nectar
 E.g Salvia, Refflesia, Aristolochia, Yucca, Ophrys speculum
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Why do animals pollinate plants?
 They get a REWARD: food! In
exchange for moving their pollen
to another flower
 Nectar – a sugary solution produced
in special flower glands called nectaries
 Nectar concentration matches energy requirements of the pollinator: bird-
and bee-pollinated flowers have different sugar conc.
 Pollen – is high in protein, some bees and beetles eat it.
 Flowers can produce two kinds of pollen: a normal and a sterile, but tasty,
kind, for the insect.
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Getting the pollinator’s
attention
 Plants advertise their pollen and nectar rewards
with
 Colors – bees see blue, yellow, UV; while birds see
red. Bats don’t see well, so flowers are white.
 Nectar or honey guides –
a visual guide for pollinator
to locate the reward (pansy flower)
 Aromas – for insects, nectar.
Can also be carrion or dung smell
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Plant Mimicry
 Some plants take advantage of the sex drive of certain insects…
 Certain orchids look like female wasps, and even smell like them!
 Males try to mate with them,
and in the process they
pollinate the plant
 The orchid gets pollinated,
but the male wasp only gets
frustrated!
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Ornithophily :
Pollination by Birds i.e. Humming bird, Sun bird, honey eater bird
Characteristics of ornithophilous flower are
 Tubular , cup shaped or urn- shaped flower
 Bright colour
 Large quantities of pollen
 Plenty of nectar
 The pistil and stamens usually project beyond the perianth lobe
 E.g Nicotiana glauca , Callistemon ,Strelitzia reginae
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Cheiropterophily
Pollination by Bat
Characteristics of Cheiropterophilous flower are
 Flower born singly or in cluster with long stalk quite away from foliage
and branches
 The flower opens only at or after dusk
 On blooming flowers emites a strong odour
 They produce quantities of nectar
 E.g Mucuna gigantea, Adansonia digitata, Kigelia africana
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Pollination.

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