Chapter 10: Plant Reproduction

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Chapter 10 Plant Reproduction
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Aim What are the 2 types of plant reproduction?
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Asexual Reproduction

• Does not involve sex cells
• One organism is producing offspring
• Most plants have this type of reproduction
• Used by plants who do not produce seeds
• Plants can be grown from a leaf, roots or stem
• the plant parts are placed into water to grow new
  roots
• Ex potatoes, grasses

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Sexual Reproduction

• Fertilization needs to occur
• Plants get help from water, wind and insects
• Female reproductive organs produce eggs
• Male reproductive organs produce sperm
• Some species have both organs on the same plant
  and can usually reproduce by itself
• Some plants have sex organs on separate plants
  and need to be near one another for fertilization
  to occur

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Aim What is the life cycle of a plant?
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Aim How do nonvascular plants reproduce?
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Importance of Spores

• Nonvascular plants do not produce seeds
• You can grow these plants from spores
• Sporophtye stage produces haploid spores in spore
  cases
• These spores can grow into plants, which produce
  sex cells
• Sporophtye stage of nonvascular plants is very
  short

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Moss Life Cycle

• Create flow chart

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• Nonvascular plants can also reproduce asexually

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Aim How do vascular seedless plants reproduce?
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The Fern Life Cycle

• Fern leaves are called fronds
• Have an underground stem called a rhizome
• Roots that anchor plant and absorb nutrients and
  water grow from the rhizome
• Fern sporophytes make their own food
• Spores produced in sori-located on fronds
• Gametophyte plant is called a prothallus, which
  also makes its own food
• Can also reproduce asexually

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• Rhizomes grow to form branches
• New fronds and roots develop from each branch
• The new rhizome can be separated and grow on its
  own
• Create flow chart of life cycle

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Aim Why are pollen and seeds important?
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Pollen

• Pollen grains have a water-resistant covering and
  contains gametophyte parts
• Sperm can be produced by these parts, which do
  not need to swim to the female part of the plant
• They are carried by pollinators, such as wind,
  gravity, water or animals
• Transfer of pollen to the female part is called
  pollination

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• When the pollen grain reaches the female part,
  sperm and a pollen tube are produced
• The sperm travels through the tube
• Fertilization occurs

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Seeds

• Following fertilization, the female part develops
  into a seed
• Seeds include an embryo, stored food and a
  protective seed coating
• The embryo grows into a plant when it is planted
• Stored food provides energy to the embryo when it
  starts to grow
• Seeds develop differently in gymnosperms and
  angiosperms

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Aim What is the life cycle of a gymnosperm?
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Gymnosperm Reproduction

• Cones are the reproductive structures
• All gymnosperms have different cones
• Ex of gymnosperms pines, firs, cedars, cycads
  and ginkgoes
• Pine tree produces male and female cones
• Gametophyte structures produced in cones
• Scale of a female cone has two ovules where eggs
  are produced
• Pollen grains are produced in the male cone
• Male cones release pollen grains in the spring

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• Wings on the pollen grain help carry it to the
  female cone
• Growth of pollen tube and sperm, and
  fertilization can take up to 15 months
• Zygote grows into an embryo and a seed develops
• It can take 2-3 years for seeds to develop and be
  released from the female cones
• Each seed grows into a new pine sporophyte

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Aim How do angiosperms reproduce?
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Angiosperm Reproduction

• The sporophyte plant produces flowers
• Flowers are reproductive organs
• They contain gametophyte structures that produce
  the sperm or egg for sexual reproduction

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Parts of the Flower

• 4 main parts-petals, sepals, stamen and pistil
• Petals
• Are the colorful parts of the flower
• Sepals
• are usually small, green, leaf-like parts
• Some are large and colorful like the flower
• Form the outside of the flower bud

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• Stamen
• Male reproductive organ
• Made up of an anther and the filament
• Pollen grain form inside the anther by meiosis
• Sperm develops in each pollen grain
• Pistil
• Female reproductive organ
• made up of stigma, style, ovary, ovule
• Stigma is sticky and is where pollen grains land
• style-sperm travels down

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• Ovary-swollen base of the pistil where ovules are
  formed
• Ovules-produce gametophyte structures, which
  produce eggs
• Pollinators of Flowers
• Large, bright flowers-insects and other animals
• An animal picks up pollen as it eats the flower,
  nectar or its pollen
• The pollen is then spread to other flowers the
  animal visits
• Other plants depend on wind, rain or gravity

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Seed Development

• After pollination and fertilization seeds develop
• Pollination happens when pollen grains land on
  the sticky stigma
• Pollen tube grows down through the style and
  enters the ovary
• Sperm travels down the tube and fertilizes the
  egg
• Zygote forms and grows into an embryo

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Aim What are the methods of seed dispersal in
seed plants?
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Seed Dispersal

• Most seeds grow only when they are placed on or
  in soil
• Gravity aids most seed into reaching the soil
• Wind dispersal helps seed plants too
• Small seeds become airborne when they are
  released by the plant
• Some have wing-like structures that allow the
  seed to move in the wind currents

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• Animals help disperse seeds
• Some seeds are eaten with fruits and pass through
  the animals digestive track to reach the soil
• Animals can also store or bury seeds
• Seeds can also attach to fur, feathers and
  clothing, which disperses them
• Water is another way seeds are dispersed
• Rain drops can knock seeds out of the fruit
• Seeds travel great distances by flowing water

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Germination

• Is the growth of a plant from a seed
• Some seeds take a few days to grow and others
  take weeks or months
• Seeds can not germinate without the right
  environmental conditions
• Begins when seed tissue absorbs water causing the
  seed coat to break open
• Energy is released from the stored food to help
  it grow