Pollination

• Pollination


  • Transfer of pollen grains from the anther to the stigma
  • Self-pollination, Cross-pollination
• Self-pollination


  • transfer of pollen grains from the anther to the stigma of the same flower or of a different flower on the same plant
  • Advantages:

  1. Only one parent is needed
  2. May inherit beneficial qualities from parent
  3. Does not depend on agents of pollination.
  4. Higher chance of pollination
  5. Less pollen and energy are wasted.

  • Disadvantages :

  1. Less genetic variation in offspring
  2. Weaker offspring

  
• Cross-pollination


  • transfer of pollen grains from one plant to the stigma of a flower in another plant of the same species.
  • Advantages:

  1. May inherit beneficial qualities from both parents
  2. Greater genetic variation in offspring
  3. Seeds are more viable (able to germinate)

  • Disadvantages:

  1. Two parents are needed
  2. Depends on external agents
  3. Lower probability of successful pollination
  4. More pollen and energy are wasted.

  
• Different species have different chromosome number, therefore cannot pair up and produce offspring.
• Pollen Allergies


  • A reaction by the immune system to fight against a specific pollen
  • Signs and symptoms :

  1. Sneezing
  2. stuffy nose
  3. runny nose
  4. watery eyes
  5. wheezing
  6. itchy throat

  • Cause : Breathing in pollen from some trees and wind-pollinated plants such as grass
• Wind pollinated flowers


  • small, dull or have no petals
  • Nectar is absent
  • Odourless
  • Large and feathery stigma
  • Long, pendulous filament
  • Small, light, smooth and abundant pollen
  • Nectar guide is absent

  
• Insect pollinated flowers


  • big, brightly coloured petals
  • nectar is present
  • fragrant
  • small and compact stigma
  • stamen is not pendulous
  • Larger, rough pollen (less abundant than wind pollinated)
  • Nectar guide is present