Plant Reproduction - Download as PowerPoint

							Plant Reproduction
    Angiosperms (flowering plants)
• Plants that protect their seeds within the body
  of a fruit.
• Make up ¾’s of all plants, including:
   – Trees, shrubs, herbs,
   grasses, water plants…
Structure of a Flower
                1. Pistil
                2. Stigma
                3. Style
                4. Ovary
                5. Stamen
                6. Filament
                7. Anther
                8. Petal
                9. Sepal
                10. Receptacle
                11. Stem
Male Reproductive Structure
              The stamen consists of
               two parts: Anther and
               Filament
              The anther is where
               meiosis occurs to
               produce haploid pollen
              The filament is a stalk
               that supports the
               anther
Female Reproductive Structure
                The pistil consists of
                 the stigma, style and
                 ovary
                The sticky stigma
                 receives the pollen
                 from the anther
                The pollen grows a
                 tube down through the
                 style
                Meiosis occurs in the
                 ovary to produce
                 haploid ovules
        Reproductive Structures
• Petals: colourful        • Sepals: surround and
 structures that attract     protect the flower bud.
  pollinators.
Pollination
      Wind, insects or other
       animals transfer pollen
       from the anther of one
       flower to the stigma of
       another
      Flowers vary
       depending on
       pollination mechanism
Pollination Animation
Pollination Vectors
        Wind Pollination: Dull, scentless
         flowers with reduced petals
        Bees/Butterfly Pollination: Bright
        color, nectaries, scent.
        They sip nectar, get pollen on coats,
        transfer pollen from flower to flower
        Bird Pollination: Nectaries, bright
        colors, tube-like flowers
        Moth Pollination: White petals,
        open at night
        Fly Pollination:Rank odor, flesh
        colored petals
• Pollen Grain                     • Anther Sac




Pollen grains contain two haploid cells produced through meiosis.
       1- The Tube cell – will grow the pollen tube.
       2- The Generative cell – will go through mitosis to create
       two sperm cells.
                          Ovary
Each ovule within an ovary has a micropyle (an opening for the
pollen tube).
The ovules’ megasporangium undergo meiosis to produce four
haploid cells (3 die leaving 1 megaspore)
The megaspore undergoes mitosis 3 times to produce 8 haploid
cells within the embryo sac.
               Fertilization
After pollen lands on the stigma, a pollen
 tube grows down through the style to ovary
Generative cell creates the two sperm nuclei
Double fertilization occurs:
  one sperm fertilizes the egg
   one sperm the two polar nuclei together
  Result of Double Fertilization
The sperm nucleus and egg nucleus join to
 form a 2n (diploid) embryo

The other sperm nucleus and the two polar
 nuclei join to form a 3n (triploid)
 endosperm. The endosperm is the food
 supply for the embryo.
First link
Seed and Fruit Development
                 After fertilization,
                  the petals and
                  sepals fall off
                  flower
                 Ovary “ripens”
                  into a fruit
                 The ovule
                  develops into a
                  seed
  Seed Dispersal Mechanisms-
Allow plants to colonize new areas and avoid
           shade of parent plant
                 Wind Dispersal - Flight mechanisms,
                 like parachutes, wings, etc.
                 Ex. Dandelion, maples, birch




                  Animal Dispersal - Fleshy fruits which
                  animals eat, drop undigested seeds in
                  feces or burrs which stick to
                  animals’ coats
Gravity Dispersal -
Heavy nuts fall to
ground and roll
ex. acorns




Water Dispersal - Plants
near water create floating
fruits
ex. coconuts