Growth and Development of Flowering Plants

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Growth and Development of Flowering Plants

• Chapter 32

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Chapter Overview

• Gametogenesis in Flowering Plants
• Embryo Development in Flowering Plants
• Germination and Growth
• Secondary Growth

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Making Pollen

• Pollen production takes place in pollen sacs of
  the anther
• Microspores formed by meiosis, then divide once
  mitotically to form pollen grains
• Generative Cell and Vegetative Cell

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How is the Female Gametophyte Produced?
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Embryogenesis

• First mitotic division results in large basal
  cell, and a smaller cell
• Basal cell divides to form the suspensor
• Smaller cell forms the spherical embryo
• Heart Stage results from fast division of shoot
  meristem
• Torpedo Stage-seed enters dormancy

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Breaking Seed Dormancy

• Why have dormant seeds?
• Breaking Dormancy?
• Nourishing the Embryo?

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Figure 32-6
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Apical Meristems

• Consist of small, undifferentiated cells
• Shoot
• stem
• leaf
• branches
• flowers
• Root
• Growth/Pattern Formation?

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Primary Root Growth

• Root Cap
• secretes mucigel
• Elongation Zone
• Differentiation Zone

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Growth of the Shoot

• More complex, as leaves, branches, stem, and
  flowers are made

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What Controls the Development of Flowers?

• Homeotic Selector Genes (Homeobox Genes)

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Wild-type Arabidopsis Flower
Apetala 2 mutant
Apetala 3 mutant
Taken From Scientific American, November, 1994
Elliot Meyerowitz
agamous mutant
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Secondary Growth

• Lateral Meristems
• vascular cambium
• produces secondary xylem and phloem
• cork cambium
• cork
• Growth Rings

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Propagating Plants Asexually

• Cuttings
• Grafting
• Cell Culture