Plant Reproduction

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Plant Reproduction
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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

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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

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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

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Accessory Structures

• The calyx consists of all the sepals, which
  protects the flower before it opens
• The corolla consists of all the petals, which
  serve to attract pollinators through color and
  scent

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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

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Pollination Animation
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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
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Bird Pollination Nectaries, bright colors,
tube-like flowers
Moth Pollination White petals, open at night
Fly PollinationRank odor, flesh colored petals
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Fertilization

• After pollen lands on stigma, a pollen tube grows
  down through the style to ovary
• Tube contains two sperm nuclei
• In ovary, there is one egg or ovule nucleus and
  two polar nuclei
• Double fertilization occurs one sperm nucleus
  fertilizes the egg, the other the two polar nuclei

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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.

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Seed and Fruit Development

• After fertilization, the petals and sepals fall
  off flower
• Ovary ripens into a fruit
• The ovule develops into a seed

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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
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Gravity Dispersal - Heavy nuts fall to ground and
roll ex. acorns
Water Dispersal - Plants near water create
floating fruits ex. coconuts
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Monocot Seed Germination

• Monocots grow straight up with coleoptile sheath
  covering shoot
• One embryonic leaf
• Seed remains underground

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Dicot Seed Germination

• Curved stem comes up out of soil
• Two embryonic leaves
• Seed goes above soil

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Parts of the Embryo

• Epicotyl - Grows into the leaves of the plant
• Hypocotyl - Becomes the stem
• Radicle - Becomes the root