The Plant Kingdom

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The Plant Kingdom

• Asexual Reproduction

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• All plants can reproduce sexually
• Many plants can also reproduce asexually

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Sexual Reproduction

• Remember several things happen during the process
  of meiosis and sexual reproduction that create
  genetic variation in offspring.
• Crossing over and independent orientation
• Random fertilization

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Asexual Reproduction

• Does not involve gametes
• Gametes are produced through the process of
  meiosis
• Only the process of mitosis is involved
• Mitosis produces genetically identical cells, so
  the offspring is identical to the parent.

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Asexual Reproduction

• Sometimes a portion of a plant forms the
  structures to make another complete plant
• Sometimes the parent plant forms small complete
  plants called plantlets on special stems or
  leaves that can grow independently

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Shoots from spreading roots

• A cattail started from a seed can produce almost
  100 shoots from spreading rhizomes in a single
  year.
• Rhizome- thick, fleshy, horizontal underground
  stems that produce leaves or leaf-bearing
  branches
• Plants like iris, bamboo, lilac, elderberry,
  grass, and many herbaceous weeds reproduce by
  rhizomes or shoots produced from spreading roots.

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Bulbs

• Bulb- collections of storage leaves that branch
  from small discs of underground stems
• Once a bulb matures, tiny bulblets develop from
  lateral buds at the base of the parent plant.
• Tulips, hyacinths, and daffodils, onion

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Tubers

• Tubers are underground stems that often produce
  abundant lateral buds, each of which may develop
  into a new plant.
• The white or irish potato is a familiar example

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Stolons

• Stolons are stems that produce plantlets at their
  nodes.
• The plantlets grow heavy enough to bend the plant
  to the ground and root themselves
• Adventitious roots- grow from a stem, a petiole,
  or a leaf
• Strawberry plants, spider plants, eelgrass, and
  bermuda grass

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Tissue Culturing

• Plant cells are like embryonic stem cells
• Most plant cells have the ability to
  differentiate into all other types of plant
  cells.
• The term describing these types of cells is
  totipotent.
• Scientists can take a single cell with the
  desired genetic makeup and culture entire plants
  from that
• This is called tissue culturing

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Pros of Asexual Reproduction

• Asexual reproduction can be induced by humans.
• Can reproduce clones that have beneficial
  characteristics
• Usually quicker than planting a seed

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Cons of Asexual Reproduction

• Genetic variation is essential for the survival
  of a species
• You might want to reproduce genetically identical
  plants because they have certain qualities that
  are beneficial, but by doing this you make the
  population susceptible to being wiped out.