Lecture 13: POLLINATION
What is pollination?
• Pollination: The transfer of pollen from the
male anther to the female stigma
Why is pollination important?
• Sexual reproduction is important for
evolution:
• Sexual reproduction produces variable...
Sexual reproduction
• In animals: It’s easy because you have separate
male and female individuals.
• In flowering plant...
Function of flower
• To attract pollinators with colorful petals, scent,
nectar and pollen
Carpel/
Overview of floral organs
Reproductive floral organs: female
• Carpel or pistil – female reproductive organs; contains:
• Stigma – is where pollen...
Reproductive floral organs: male
• Stamen – male floral organ, consists of:
• Anther – part of the stamen that produces ...
Non-reproductive floral organs
• Petals – whorl of flower organs that are often
brightly colored to attract pollinators ...
Pollination and Fertilization
• Pollen contains TWO nuclei: a sperm nucleus
and tube nucleus
• Sperm nucleus is protect...
Pollination and Fertilization
• For pollen sperm to successfully fertilize the
egg, there must be pollination: a method ...
Double Fertilization
• Double fertilization occurs: One sperm nucleus
(1n) fertilizes the egg, producing a zygote (2n) ...
Strategies to avoid self-pollination
• Perfect flowers have both male and female organs, so
plants have strategies to av...
How do plants get pollen from one
plant to another?
• Because plants are rooted in the ground, they
must use different ...
ANIMALS
• Many flowering plants rely on animals for cross-pollination:
• Insects – bees, wasps, flies, butterflies, moth...
Coevolution
• Coevolution – interactions between two
different species as selective forces on each
other, resulting in ...
A word about pollen…
• The shape and form of pollen is related to its
method of pollination…
• Insect-pollinated specie...
Palynology: the study of pollen
• Palynology is useful in many fields:
• Petroleum geology – fossil pollen can determine...
Animal pollinators: Bees
• Bees – are the most important group of flower
pollinators
• They live on the nectar and feed...
Butterflies and moths
• Also guided by sight and smell
• Butterflies can see red and orange
flowers
• Usually shaped a...
Flies and beetles
• Flies like flowers that smell
like dung or rotten meat.
• Lay their eggs there, but larvae
die due...
Birds
• Birds have a good sense
of color, they like yellow or
red flowers…
• But birds do not have a good
sense of sm...
Mammals: bats and mice
• Bats pollinate at night,
so flowers are white
• Mouse-pollinated flowers
are usually inconspi...
Why do animals pollinate plants?
• They get a REWARD: food! In
exchange for moving their pollen
to another flower
• Ne...
Getting the pollinator’s attention
• Plants advertise their pollen and nectar rewards
with
• Colors – bees see bblluuee...
Plant Mimicry
• Some plants take advantage of the sex drive of
certain insects…
• Certain orchids look like female wasp...
Watch video, take notes, questions
• What causes “hay fever”? __________________
• What carries pollen released by grass...
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Pollination '' Reproduction in Plants"

Pollination is the transfer of pollen grain from the anther to the stigma of the flower
Published on: Mar 4, 2016
Published in: Education      
Source: www.slideshare.net


Transcripts - Pollination '' Reproduction in Plants"

  • 1. Lecture 13: POLLINATION
  • 2. What is pollination? • Pollination: The transfer of pollen from the male anther to the female stigma
  • 3. 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…)
  • 4. Sexual reproduction • In animals: It’s easy because you have separate male and female individuals. • In flowering plants: Not so easy, because most flowers have both male and female parts in them, called perfect flowers. • So flowering plants have evolved special ways to insure outbreeding/outcrossing – and to prevent inbreeding.
  • 5. Function of flower • To attract pollinators with colorful petals, scent, nectar and pollen Carpel/
  • 6. Overview of floral organs
  • 7. Reproductive floral organs: female • Carpel or pistil – female reproductive organs; contains: • 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 • Plants have style! carpel or pistil ovary
  • 8. 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
  • 9. 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
  • 10. Pollination and Fertilization • Pollen contains TWO nuclei: a sperm nucleus and tube nucleus • Sperm nucleus is protected in gametophyte tissue (pollen can travel in the air)
  • 11. Pollination and Fertilization • For pollen sperm to successfully fertilize the egg, there must be pollination: a method to get the pollen from the male anther to the stigma. • Pollen sticks to the stigma, starts growing a pollen tube • Fertilization begins when tube begins to grow toward the egg
  • 12. Double Fertilization • Double fertilization occurs: One sperm nucleus (1n) fertilizes the egg, producing a zygote (2n)  which becomes the plant embryo inside the seed • Another sperm nucleus fuses with the polar nuclei, resulting in a triploid endosperm (3n) • Endosperm is a source of food for the young embryo. Endosperm
  • 13. Strategies to avoid self-pollination • Perfect flowers have both male and female organs, so plants have strategies to avoid self-pollination: • 1. Timing – male and female structures mature at different times • 2. Morphological – structure of male and female organs prevents self-pollination (imperfect flower) • 3. Biochemical – chemical on surface of pollen and stigma/style that prevent pollen tube germination on the same flower (incompatible)
  • 14. How do plants get pollen from one plant to another? • Because plants are rooted in the ground, they must use different strategies: • WIND POLLINATION: • Gymnosperms and some flowering plants (grasses, trees) use wind pollination. • Flowers are small, grouped together • Not a very efficient method (too chancy and wasteful)
  • 15. ANIMALS • Many flowering plants rely on animals for cross-pollination: • Insects – bees, wasps, flies, butterflies, moths • Birds – hummingbirds, honey creepers • Mammals – bats, mice, monkeys • Even some reptiles and amphibians!
  • 16. Coevolution • Coevolution – interactions between two different species as selective forces on each other, resulting in adaptations that increase their interdependency. • Animal-flowering plant interaction is a classic example of coevolution: • 1. Plants evolve elaborate methods to attract animal pollinators • 2. Animals evolved specialized body parts and behaviors that aid plant pollination
  • 17. A word about pollen… • The shape and form of pollen is related to its method of pollination… • Insect-pollinated species have sticky of barbed pollen grains • Wind-pollinated species is lightweight, small and smooth (corn pollen)
  • 18. Palynology: the study of pollen • Palynology is useful in many fields: • Petroleum geology – fossil pollen can determine if a field will have oil-rich deposits • Archeology – studying ancient pollen samples, archeologists can determine agricultural practices, diet, etc. • Anthropology – uses of pollen in rituals • Criminology – to determine the whereabouts of an individual, examine pollen clinging to clothes • Aerobiology – to determine what plants cause hay fever and allergic reactions – in landscaping
  • 19. Animal pollinators: Bees • Bees – are the most important group of flower pollinators • They live on the nectar and feed larvae, also eat the pollen. • Bees are guided by sight and smell • See yyeellllooww and blue colors, also ultraviolet light (not red) • Flowers have “honey guides” and bee landing platforms..
  • 20. Butterflies and moths • Also guided by sight and smell • Butterflies can see red and orange flowers • Usually shaped as a long tube because of insect’s proboscis – to get nectar • Moth-pollinated flowers are usually white or pale, with sweet, strong odor – for night pollination.
  • 21. Flies and beetles • Flies like flowers that smell like dung or rotten meat. • Lay their eggs there, but larvae die due to lack of food • Beetles pollinate flowers that are dull in color, but have very strong odor
  • 22. Birds • Birds have a good sense of color, they like yellow or red flowers… • But birds do not have a good sense of smell, so bird-pollinated flowers usually have little odor. • Flowers provide fluid nectar in greater quantities than insects • Hummingbird-pollinated flowers usually have long, tubular corolla • Pollen is large and sticky
  • 23. Mammals: bats and mice • Bats pollinate at night, so flowers are white • Mouse-pollinated flowers are usually inconspicuous, they open at night
  • 24. 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.
  • 25. Getting the pollinator’s attention • Plants advertise their pollen and nectar rewards with • Colors – bees see bblluuee,, yyeellllooww, UV; while birds see rreedd. 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
  • 26. 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!
  • 27. Watch video, take notes, questions • What causes “hay fever”? __________________ • What carries pollen released by grasses (corn)? ________ • A flower with both male/female structures is a ___flower • What increases genetic variability in a population?____ • What color flowers do birds pollinate? Bees? Moths? • Why are bird-pollinated flowers usually odorless?______ • What time of the day do bats pollinate?______________ • What two rewards do insects get from flowers?________ • Flies and butterflies reach the nectar using a long ______ • Flies pollinate flowers that smell like rotting __________ • Why do some orchids look and smell like wasps?______