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Ch 24 Plant Reproduction

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Ch 24 Plant Reproduction Powered By Docstoc
					1.   Classify Which plant structures are male sexual
     organs and which are female sexual organs
2.   Apply Concepts Relate the characteristics of
     angiosperms reproduction to angiosperm success
3.   Review Define vegetative reproduction
4.   Compare and Contrast Make a compare contrast
     table comparing alternation of generations in
     flowering plants and green algae (22.2)
CH 24 PLANT REPRODUCTION AND RESPONSE
          24.1 Reproduction in Flowering Plants
     Structure of Flowers
   Reproductive organs that are composed of four
    kinds of specialized leaves:
     Sepals,   petals, stamens, and carpels.
      Sepals
   Outermost circle of floral parts
   Enclose the bud before it opens
   Protect the flower while it is developing.
     Petals
   Found just inside the sepals
   Colors, number, and shapes of such petals attract
    insects and other pollinators to the flower.
      Stamen
   Male parts of the flower
   Consists of a stalk called a filament with an anther
    at its tip
   Anther
     Structure   that produces pollen grains.
     Carpels
   Produce and shelter the female gametophytes and
    seeds
   Ovary
            one or more ovules where female
     Contains
     gametophytes are produced.
      Carpels
   Style
     Stalk   of carpel
   Stigma
     Stickyor feathery portion at tip of carpel to capture
      pollen.
      Carpel
   Pistil
     Single   carpel or several fused carpels.
Angiosperm Life Cycle
   Fertilization in angiosperms is distinct from other
    plants
   Two fertilization events take place- one produces
    the zygote and the other a tissue, called
    endosperm, within the seed.
Angiosperm Life Cycle
   Alternation of generations between a diploid
    sporophyte phase and a haploid gametophyte
    stage
   Male and female gametophytes live within the
    tissues of the sporophyte.
     Development of Male Gametophytes

   The male gametophytes (pollen grains) develop
    inside anthers
   Meiosis produces four haploid spore cells.
    Development of Male Gametophytes

 Each spore undergoes one mitotic division to
  produce the two haploid nuclei of a single pollen
  grain
 Two nuclei are surrounded by a thick wall that
  protects the
 male gametophyte.
     Development of Female Gametophytes

   Develop inside each carpel of a flower
   Ovules (future seeds) are enveloped in a protective
    ovary (future fruit).
     Development of Female Gametophytes

   Single diploid cell goes through meiosis to produce
    four haploid cells, three of which disintegrate.
     Development of Female Gametophytes

   Remaining cell undergoes mitosis, producing eight
    nuclei
   Embryo sac
     Eight   nuclei and the surrounding membrane.
Development of Female Gametophytes

   Cell walls form around six of the eight nuclei
   One of the eight nuclei near the base of the
    gametophyte, is the nucleus of the egg (female
    gamete)
   Will fuse with male gamete, form zygote and
    become sporophyte if fertilization occurs.
Pollination
   Transfer pollen to the female portions of the
    flower
     Can   use wind or an animal pollinator
   Wind pollination is less efficient
     Relieson favorable weather and sheer numbers of
      pollen grains.
Animal Pollinated Plants
   Variety of adaptations to attract and reward
    animals
     Suchas bright colors and sweet nectar
     Animals have evolved body shapes to reach nectar
      deep within certain flowers
   Insect pollination
     Plant benefits- efficient pollination
     Insect benefits- source of food.
     Fertilization
    Pollen grain lands on the
     stigma of a flower
    Pollen tube begins to grow
    Pollen grain has two cells
    1.   Cell divides and forms two
         sperm cells
    2.   Cell becomes the pollen
         tube.
   Pollen tube grows into the style
   Reaches the ovary
   Enters an ovule.
Double Fertilization
   One of the sperm nuclei fuses with the egg nucleus
    to produce a diploid zygote
   Other sperm nucleus fuses with two polar nuclei in
    the embryo sac to form a triploid (3N) cell or
    endosperm
   Endosperm
     Food-rich tissue known which nourishes the seedling
      as it grows.
   Flowering plant spends very little in the way of
    food resources on producing seeds from ovules
    until double fertilization has actually taken place
   Make more seeds.
Vegetative Reproduction
   Asexual reproduction
   Enables a single plant to produce offspring
    genetically identical to itself by mitosis
   Enables a single plant to produce offspring
    genetically identical to itself by mitosis.
   New plants may grow from roots, leaves, stems, or
    plantlets
   Single plant can reproduce quickly.
Good
   Single plant produces genetically identical
    offspring, enabling well-adapted individuals to
    rapidly fill a favorable environment.
Bad
   Does not produce new combinations of genetic
    traits, which may be valuable if conditions in the
    physical environment change.
   Grafting
     Method   to reproduce
      seedless plants and varieties
      of woody plants that cannot
      be propagated from cuttings
     Plants need to be closely
      related.

				
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posted:2/29/2012
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