Plant Reproduction and Responses

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• Plant Reproduction and Responses

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Alternation of Generations

• Haploid and diploid generations take turns
  producing each other
• Diploid sporophyte (produces haploid spores by
  meiosis, spores divide mitotically and give rise
  to multicellular male and female haploid plants)
• Haploid gametophyte (by mitosis and cellular
  differentiation, these develop and produce
  gametes fertilization results in diploid
  zygotes, which divide by mitosis and form new
  sporophytes)

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Floral organs

• From outside in
• sepals
• petals
• stamens male reproductive organs
• -made up of anther and filament
• carpels female reproductive organs
• -made up of ovary, style, stigma
• Site of attachment on the stem receptacle

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• Male gametophytes are the pollen grains
• Female gametophytes are embryo sacs

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Figure 38.1 Simplified overview of angiosperm
life cycle
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 The Structure of a Flower
Section 24-1
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Double fertilization

• Pollen grain absorbs moisture and germinates once
  on a receptive stigma
• (by germinates, mean grows a pollen tube that
  entends down between the cells of the style
  toward the ovary)
• The generative cell divides by mitosis and forms
  two sperm
• (germinated pollen grain is the mature male
  gametophyte)

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Figure 38.9 Growth of the pollen tube and double
fertilization
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Figure 244 The Life Cycle of a Gymnosperm
Section 24-1
Haploid (N) Diploid (2N)
MEIOSIS
FERTILIZATION
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The Life Cycle of an Angiosperm
Section 24-1
Haploid (N) Diploid (2N)
MEIOSIS
Ovule
FERTILIZATION
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Compare/Contrast Table
Section 24-1
Comparing Plant Propagation Methods
Method Procedure
Cuttings
Grafting
Budding
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Plant responses

• -Hormones
• -Light -- Phototropisms
• -Gravity -- Gravitropisms
• -Touch -- Thigmotropisms

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Hormones

• Auxin cell elongation (primary growth and
  secondary)
• Cytokinins cell division, differentiation,
  apical dominance
• Gibberellins stem elongation, fruit growth
• Abscisic acid slows down growth, seed dormancy,
  drought stress
• Ethylene fruit ripening, leaf abscission,
• Brassinosteroids inhibits root growth, slows
  down leaf abscission, promotes differentiation of
  xylem