Reproduction in plants

• Structures of a Plant


  • Flower
  • Leaf
  • Stem
  • Shoot
  • Root
  • Buds

  
• Flower


  Sexual reproduction: to produce
• Stem


  Transport of material up and down the plant and to hold plant up
• Buds


  To produce new leaves, branches or flowers

  
• Root


  To anchor the plant and to absorb water and minerals
• Functions of the plant structure
• Sexual Reproduction

  1. Production of offspring by the fusion of male gamete (sperm/ pollen) and female gamete (egg / ovule)

  2. The gametes are produced by Meiosis

  3. The gametes fuse by Fertilisation
• Structure of a flower


  • Petal
  • Stigma
  • Style
  • Ovule
  • Carpel
  • Anther
  • Filament
  • Stamen
  • Sepal
  • Ovary
  • Nectary

  
• Petal


  To attract pollinators
• Stigma


  Receives the pollen
• Style


  Holds the stigma up and path of pollen tube
• Ovule


  Female gamete. Develops into the seed
• Carpel


  Female organ
• Anther


  Produces male gamete: Pollen
• Filament


  Holds the anther up
• Stamen


  Male organ
• Sepal


  Protects the flower bud
• Ovary


  Contains the ovules and eventually develops into the 'Fruit'
• Nectary


  To attract pollinators
• Pollination


  The transfer of pollen from an anther to a Stigma
• Pollination types

  • Insects
  • Wind
• Insect-pollinated flower


  • Stamen enclosed so that insect can make contact
  • Sweet nectar to attract insects
  • Sticky stigma so that pollen grains attach
  • Large colourful petals to attract insects
  • Sticky pollen grains - stick to insects' bodies
• Wind-pollinated flower


  • Hairy/feathery stigma to trap wind blown pollen
  • Sticky stigma so that pollen grains attach brought by insects rubbing along it
  • Receptive stigma exposed
  • Flowers tightly massed to form a spike
  • Anther exposed to wind - pollen can be blown away easily
  • Large numbers of small and light pollen grains
• Comparison of insect and wind pollinated flowers

  
• Fertilisation


  1. Pollen grain grows a tube down the style

  2. Pollen tube grows into ovary and enters ovule - pollen grain nucleus moves down tube

  3. Fertilisation - male nucleus fuses with the egg cell nucleus
• After fertilisation, fertilised ovule becomes a seed and ovary becomes a fruit
• Parts of a seed


  • Cotyledon (food storage-Starch)
  • Plumule (young shoot)
  • Radicle (young root)
  • Testa: outside 'coat'
  • Scar... where the ovule / seed was attached to the ovary wall
• Germination


  1. Radicle (young root) emerges

  2. Plumule (young shoot) emerges

  3. Shoot with leaves for photosynthesis

  4. Roots for anchoring and absorbing water and minerals
• Conditions required for germination


  • Water
  • Oxygen
  • Warm temperature
• Experiment to investigate conditions required for germination
• Asexual Reproduction


  Production of offspring without the production or fusion of gametes. Offspring produced by part of an organism separating from a single parent
• Asexual Reproduction (natural)


  • Strawberry Runners
• Asexual Reproduction (artificial)


  • Cuttings: A young shoot is cut off and put in water to encourage new root growth
• Comparison of Sexual and Asexual Reproduction


  • Gamete Production?
  • Type(s) of Cell Division
  • Fertilisation?
  • Genetic Variation in offspring?