Plant Reproduction

• Reproduction


  The process by which new individual organisms called the offsprings, are produced from their "parents"
• Types of reproduction


  • Asexual reproduction
  • Sexual reproduction
• Asexual reproduction


  • Only one organism is involved
  • No gametes or fertilization
  • Quick process
  • All offspring are identical, no variation
• Sexual reproduction


  • Usually requires more than one organism
  • Requires male and female gametes and fertilization
  • Slower process
  • All offspring are different from each other, there is variation
• Asexual reproduction


  A form of reproduction which requires only one parent, with no exchange of genetic material and fertilization
• Clone


  Offspring produced by asexual reproduction that are identical to one another
• Asexual reproduction


  • Advantage: very fast
  • Disadvantage: no variation in offspring
• Asexual reproduction


  • Binary fission
  • Budding
  • Spore formation
• Binary fission


  1. Genetic material replicates

  2. Each piece moves to opposite sides of the cell

  3. Two new daughter bacteria form
• Bacteria


  • Unicellular organisms
  • Genetic material is free in the cytoplasm, not surrounded by a nuclear membrane
• Protists


  • Unicellular organisms
  • Have a proper nucleus
• Budding


  Cell division where a smaller daughter cell forms on the side of a larger mother cell
• Organisms that reproduce by budding

  • Yeast
  • Hydra
• Spore formation


  Production of specialized spherical cells that will later grow into adult organisms
• Organisms that reproduce by spore formation

  • Fungi
  • Mosses
  • Ferns
• Sexual reproduction


  Requires two living things, a male and a female, that produce sex cells or gametes which join to form a zygote
• Sexual reproduction


  • Advantage: variation in offspring
  • Disadvantage: slower process
• Flower


  The organ of sexual reproduction in flowering plants
• Parts of a flower

  • Receptacle
  • Sepals
  • Petals
  • Stamen
  • Carpel
• Stamen


  The male reproductive part of the flower, consisting of an anther that produces pollen grains and a filament that holds the anther upright

  
• Carpel


  The female part of the flower, consisting of a stigma, style, ovary, and ovules

  
• Ovule


  Spherical structure in the ovary that contains an egg cell to be fertilized
• Pollination


  Transfer of pollen from the anther to the stigma of a flower

  
• Types of pollination


  • Self-pollination
  • Cross-pollination

  
• Self-pollination


  • Pollen transferred from anther to stigma of same plant
  • Anthers and stigmas ripen at same time, stigma below anthers

  
• Cross-pollination


  • Pollen transferred from anther of one plant to stigma of another plant of same species
  • Anthers and stigmas ripen at different times, stigma above anthers

  
• Cross-pollination is better than self-pollination, producing stronger, healthier plants
• Mechanisms of pollination


  • Insect pollination
  • Wind pollination
• Insect pollination


  • Insects like bees, butterflies, and moths carry pollen from flower to flower
  • Flowers have nectar, colourful/scented petals, and sticky pollen to attract insects

  
• Wind pollination


  • Wind carries pollen from flower to flower
  • Flowers are small, inconspicuous, without nectar or scent
  • Produce large amounts of pollen, with anthers and stigmas exposed
• Fertilization in plants


  1. Pollen tube grows from stigma to ovule

  2. Male gamete in pollen fuses with female gamete in ovule to form zygote

  
• Fertilization in a plant

  1. Pollen grain on stigma germinates pollen tube

  2. Pollen tube grows into stigma and down style

  3. Male sex cell with nucleus moves down tube

  4. Pollen tube reaches ovule and enters through micropyle

  5. Male nuclei enter ovule and fuse with female nuclei to form zygote

  
• Fruit and seed formation

  1. Petals, anthers, stigma and style fall off

  2. Fertilized ovules develop into seeds

  3. Fertilized egg cell develops into embryo plant and cotyledons

  4. Ovule wall becomes seed coat

  5. Ovary swells and develops into fruit

  
• Seed dispersal methods


  • Wind dispersal
  • Water dispersal
  • Animal dispersal
  • Explosive dispersal

  
• Seeds


  • Develop from ovules after fertilization
  • Consist of miniature plant (embryo) and modified leaves (cotyledons)
  • Enclosed in tough coat (testa)

  
• Testa


  Seed coat that protects seed from insects, bacteria and fungi

  
• Micropyle


  Hole through which water enters seed to start germination
• Plumule


  Embryo shoot containing small leaves and growing point
• Radicle


  Embryo root, first structure to emerge during germination

  
• Cotyledons


  Modified leaves containing food reserves used during early germination