FLOWERS

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FLOWERS

• PLANT REPRODUCTION

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• PARTS OF THE FLOWER
• TYPES OF FLOWERS
• DICOT VS MONOCOT
• POLLINATION
• FERTILIZATION
• SEED FORMATION
• FRUIT
• ASEXUAL REPRODUCTION

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PARTS OF A FLOWER

• Flowers are modified leaves.
• Receptacle - stem tip that contains a flower.
• NONESSENTIAL PARTS ( not involved in
  reproduction)
• Sepals - leaf like structures that surround the
  flower before it blooms, protect the developing
  flower.
• Calyx - all the sepals together.
• Petals - colorful, showy part of flower, attract
  pollinators, mostly insects.
• Corolla - all the petals together.

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• ESSENTIAL FLOWER PARTS ( directly involved in
  reproduction)
• Stamens - the male parts
• Anther - tip that contains the pollen
• Filament - stalk like support for the anther
• Pistil - the female parts
• Ovary the base part that can be divided into
  carpels ,different chambers where seeds (eggs)
  will develop.
• Style stalk like part that holds the stigma
• Stigma the tip of the style, traps pollen.

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TYPICAL COMPLETE FLOWER
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TYPES OF FLOWERS

• Perfect flower has both male (stamen) and
  female (pistil) parts on one flower.
• Imperfect flower lack one of the sex parts in
  the flower.
• Male and female flowers on the same plant are
  dioecious.
• Male flowers and female flowers on different
  plants are monoecious.

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NUMBER PATTERNS OF PLANTS

• Monocots flower parts generally in 3s or
  multiples of 3.
• Gladiolas have 3 sepals, 6 petals, 3 stamen, one
  pistil with 3 stigmas, an ovary with 3 carpels.
• Dicots flower parts are mostly 4s and 5s.
• 5 sepals, 5 petals, 10 stamen, 5 separate pistils.

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POLLINATION

• When pollen is transferred from the anther to the
  stigma of the pistil.
• Cross pollination - transfer of pollen from one
  plant to another plant.
• Self pollination - transfer of pollen from anther
  of flower to the stigma of the same flower.
• Most plants with bright colorful flowers are
  pollinated by animals, to attract them flowers
  make nectar (a sweet fluid at the base of the
  flower)
• Pollinators - bees, hummingbirds, moths,
  mosquitoes, butterflies, beetles, and bats.

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POLLINATION
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FRUIT DEVELOPMENT
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FERTILIZATION

• After the pollen lands on the stigma
  (pollination) it must travel down to the eggs in
  the ovary.
• Pollen grains contain two nuclei
• one (the tube cell) to digest a pathway through
  the stigma, style, and ovary wall to the eggs
  in the carpels
• the other (a haploid generative cell) follows and
  divides forming two sperm cells.
• DOUBLE FERTILIZATION
• one fuses with the egg and forms a diploid
  zygote.
• The other fuses with the two polar egg nuclei to
  form triploid tissue called endosperm (food for
  the embryo until the plant grows)

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PHOTOPERIODISM

• The length of daylight (actually the length of
  darkness) determines when plants will flower.
• SHORT-DAY plants strawberries bloom when days
  are shorter than night, in the fall
• LONG-DAY plantscarnations bloom as the daylight
  hours increase in the spring.
• DAY-NEUTRAL plants most plants are this way,
  blooming is controlled by temp., moisture, or
  something other than day length.

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SEED GERMINATION

• Mature seeds have the ability to survive
  unfavorable conditions by remaining dormant, a
  period of inactivity.
• Plenty of water, warm temps., and enough oxygen
  usually ends dormancy.
• Germination is the beginning of the development
  of seeds into new plants.
• Some seeds need special conditions to germinate
• Must pass through an acid environment
• Exposed to fire
• A period of freezing temps.

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SEEDS
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SEEDS
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FRUITS

• The ovary ripens into a fruit which surrounds the
  seeds.
• SIMPLE FRUIT one ovary
• Fleshy berry or drupe
• Dry
• Dehiscent - split open at maturity
• Legume, follicle, capsule, silique
• Indehiscent - dont split open
• Achene, grain, samara, nut
• AGGREGATE cluster of ripened ovaries, one
  flower
• MULTIPLE cluster of ripened ovaries, several
  flowers

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ASEXUAL REPRODUCTION

• VEGETATIVE PROPAGATION produces new plants by
  methods other than flowers.
• Examples
• Runners, tubers, bulbs, and corms
• Rooting of cuttings off another plant, stems or
  leaves.
• Grafting one plant onto another