Plant Reproduction

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Chapter 9

• Plant Reproduction

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Section 1

• Introduction to Plant Reproduction

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Types of Reproduction

• Asexual plant reproduction-when plants reproduce
  from other plant cells, identical to parent.
• Example- when a leaf sprouts into a new plant.

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Sexual Reproduction

• Sexual plant reproduction-when a sperm and egg
  cell combine to form a seed for a new plant.
• Example-when a bee takes pollen to a flower an
  seeds form.

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Reproductive organs

• Plants can have male and female reproductive
  organs on same plant or separate plants.
• Example- holly plants have male and female
  plants.
• Pea plants have male and female on same plant.

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Plant Life Cycles

• 1.)Gametophyte stage-when cells in reproductive
  organs undergo meiosis and produce haploid cells
  called spores.
• 2.)Sporophyte stage-when fertilization occurs by
  the joining of haploid sex cells. Cells have
  diploid number of chromosomes.

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Section 2

• Seedless Reproduction

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Spores

• Spores-haploid cells produced during gametophyte
  stage, divide by mitosis and form plants that
  will produce sex cells.

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Nonvascular Seedless Plants

• Moss is a nonvascular seedless plant-water moves
  from cell to cell.

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Moss Life Cycle

• Gametophyte stage-green low growing mass of
  plants.
• Sporophyte stage-brown stalks grow up from green
  plant capsule on end of stalk has millions of
  spores which are released when conditions are
  right.
• Can produce asexually if small piece of plant
  breaks off and falls into moist soil.

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Vascular Seedless Plants

• Vascular Plants-use vascular tissue to transport
  water from roots to plant.
• A Fern is a vascular plant.

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Fern Life Cycle

• Frond-fern leaf
• Rhizome-underground fern stem
• Sori-structures that produce fern spores
• Prothallus-small heart shaped gametophyte
• Picture of new frond opening

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Fern Life Cycle

• Sporophyte stage-plants have fronds, rhizome,
  produce food by photosynthesis. They have sori
  that produce spores

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Fern Life Cycle

• Gametophyte stage- grows from spore into
  prothallus.
• Ferns can also reproduce asexually- a branch can
  be taken off and planted to make a new plant.

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Section 3

• Seed Reproduction

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Seed Reproduction

• Pollien-spores turn into pollen in seed plants.
• Pollen grain-has water resistant covering and
  contains gametophyte parts that produce sperm.
• Pollination-transfer of pollen to female part of
  plant

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Seeds

• 3 parts-seed coat, stored food, and embryo
• Gymnosperms-seeds produce in cones
• Angiosperms- seeds produce in flowers

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Gymnosperm Reproduction

• Male cones produce pollen
• Female cones contain ovules that contain eggs
• Then pinecones open to reveal seeds.

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Angiosperm Reproduction

• Use flowers to reproduce
• 4parts of a flower
• Petals
• Sepals-small leaf outside of petals
• Stamen-male reproductive organ
• Pistil-female reproductive organ with the swollen
  base called ovary

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Importance of flowers

• Large flowers with bright petals attract insects
  and other animals to spread pollen.
• Flowers with small petals and drab color use
  wind, rain and gravity to spread pollen.
• Flowers that open at night are yellow or white
  and have strong odor to attract animals.

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Angiosperm Seeds

• Pollen lands on stigma.
• Pollen tube grows down through style to ovary and
  ovule.
• The sperm travels down the pollen tube and
  fertilizes ovule.
• A zygote forms and grows into plant embryo.

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Seed Development

• Ovule develops into the stored food and seed coat
  around embryo.
• Stored as cotyledons in peanuts.
• Stored as endosperm in corn.

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Seed Dispersal

• Wind
• Gravity
• Water
• Animals-when eaten and passed through digestive
  tract.
• Animals-carried on fur.

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Seed Germination

• Seeds germinate when environmental conditions are
  right.
• The seed first absorbs water to burst seed coat
  and begin germination.
• Then chemical reactions occur to release energy
  from stored food.
• Then it takes root and the stem and leaves grow.

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The End