Mitosis, Meiosis, Pollination, and Fertilization Oh MY

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Mitosis, Meiosis, Pollination, and
FertilizationOh MY!
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Genotype vs Phenotype

• genotype genetic makeup of an organism
• phenotype visible result of the interaction
  between genotype and environment

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Cell Division

• Mitosis - basis of asexual propagation
• (toes)
• Meiosis - basis of sexual propagation
• (me)

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Mitosis

• Mitosis - nonreductive cell division -duplication
• Cell divisions in shoot root tip and vascular
  cambium

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Mitosis

• Chromosomes are replicated
• Identical pairs of chromosomes go to each of the
  cells
• produce cell with exact genetic information
• new cells have same characteristics of heredity
  as mother cell
• same genotype

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Mitosis
Interphase
Prophase
Metaphase
Anaphase
Telophase
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Mitosis Plant Propagation

• Totipotency - vegetative cell has all the genetic
  information needed to reproduce the full-sized
  plant and to initiate the seedling cycle (next
  generation)
• Clones - result of mitotic cell division
• asexual or vegetative propagation
• used for highly heterozygous plant materials

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Meiosis

• Meiosis -reductive cell division
• homologous chromosomes separate from each other
  without replicating
• half the of chromosomes (n) as mother cell
• ex. diploid to haploid
• 2n to 1n
• gamete formation
• microspore
• megaspore

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Pollination Fertilization pg. 73 (Angiosperm)

• haploid gamete produced by meiosis
• microspore divides mitotically to produce pollen
  grain
• megaspore - 3 mitotic division to produce embryo
  sac containing
• egg cell polar nuclei

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• Anther
• Cross-
• Section

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Pollination Fertilization

• Pollination pollen transferred to stigma of
  pistil/carpel
• Pollinizer pollen source
• Pollinator bees, insects

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Pollination Fertilization

• pollen tube (2 sperm cells) grows down style to
  ovule
• one sperm unites with ovule to form zygote
• divides to produce embryo
• one sperm cell unite with two polar nuclei in
  embryo sac
• form endosperm - food storage tissue
• mitotic divisions result in embryo development

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Self Pollination

• Pollen from the same flower, or another flower of
  same genotype
• Self pollination can result in inbreeding
• used to produce lines
• pure or inbred lines used for production of
  hybrid seed
• Inbreeding depression

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Cross Pollination

• Pollen from one cultivar (genotype) fertilizes
  another genotype.
• Apples
• Jonathan,Delicious
• Results in genetic recombination
• Dioecious
• Incompatibility
• Sterility
• Dichogamy

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Xenia

• Effect of pollen on endosperm and embryo
• Sweet corn
• Field corn