Colorado AgriScience Plant Science

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Colorado AgriSciencePlant Science

• Unit 4 Plant Reproduction Genetics
• Lesson 2 Sexual Reproduction in Plants

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Sexual Reproduction

• Involves flowers, fruit, seed
• Sperm from male flower fuses w/the ovum of the
  female plant
• Results in recombination of DNA
• Results in genetically unique individual
• Allows plants to adapt evolve to environmental
  change

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Pollination

• Transfer of pollen from the male to the female
  part of the plant(s)
• How pollination occurs
• Self-Pollination
• Pollen from a plant pollinates a flower on the
  same plant
• Cross-Pollination
• Pollen from a plant pollinates a flower on a
  different plant

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Fertilization

• Necessary in flowering plants in order for a seed
  to develop
• Double Fertilization
• Unique to plants
• Two sperm nuclei involved in fertilization
• 1st fertilization occurs when one sperm fuses
  with the egg creating a zygote
• 2nd fertilization occurs when the 2nd sperm
  nucleolus fuses with the two nuclei in the embryo
  sac
• Results in the formation of the endosperm

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Fertilization

• Hybrid
• Fertilization occurring from parents that are
  genetically different
• Advantages
• Best traits of each parent is expressed
• Results in Hybrid Vigor
• Increased growth, drought resistance, or insect
  resistance is possible

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Fertilization Genetics

• Genetic information is stored in every cell of
  the plant in DNA
• Segments of DNA, called genes, establish the code
  for plant appearance and traits
• Genes are arranged into a set of chromosomes

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Fertilization Genetics

• Diploid
• Normal sets of cells containing two chromosomes
• Haploid
• Sex cells contain one chromosome
• When fertilization occurs, the single sets of
  chromosomes are combined into the double set, one
  from each parent
• Results in traits from each parent to be passed
  on to offspring.

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