Chap 5. Differentiation and Development

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Chap 5. Differentiation and Development

• General Information
• Plant Growth Hormones
• Vegetative Physiology
• Reproductive Physiology

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1. Process of Differentiation

• Differential growth in cell and tissues
• Orderly and systematic in mitotic cell division
• Genetically controlled development
• by gene activation and deactivation
• Also influenced by external environment
• Tissue and organ differentiation controlled by
  plant growth hormones that are produced
  indifferent parts of plants

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Influence of IBA Treatment on Root Formation
Jojoba
Peach
Ficus
Cuttings treated with IBA 1-control, 2-50
ethanol, 3-1000 ppm IBA, 4-2000 ppm IBA, 5-4000
ppm IBA
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Enhancement of Seed Germination by GA Treatment
Penstemon parryi
Seeds of Desert Beard Tongue (Penstemon parryi)
is difficult to germinate due to seed dormancy
(see 1 above). Treatment of seed with 200 ppm
GA3 for 24 hours leads to 95 germination (see 2
above).
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Seed treatment with GA3 often ends up with
elongated seedlings control (left), GA3 treated
(right)
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Tissue culture of leaf discs of Salpiglossis
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Influence of cytokinin and auxin on
differentiationof callus tissues in vitro,
Salpiglossis
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Callus proliferation and root production occur
under a combinationof low cytokinin and high
auxin concentrations in the medium
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Shoot differentiation occurs under a
combinationof high cytokinin and low auxin
levels in the medium
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Shoots induced on callus grown in vitro can be
divided and rooted as clonal propagules
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Flowering Salpiglossis plants which have been
cloned from leaf disc cultures
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Ethephon application converts male flowersto
female flowers in muskmelon
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An example of flower sex expression in a
muskmelonplant after treatment with ethephon
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Muskmelon fruits developed from ethephon-induced
female flowers are often elongated top row
(control), bottom row (ethephone-treated)
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Easter lily plants grown in greenhouse often show
elongated stems which makes boxing for mass
market distribution difficult
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Some Chemical Growth Retardants
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Easter Lily Height Control by Sumagic
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Influence of DIFDifference between Day and Night
Temperatures
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Plant height control on Liatrus (gay feather) by
growth retardant application (left-treated,
right-control)
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MetaxeniaInfluence of Pollination on Fruit Set
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Influence of Pollination onStrawberry Fruit
Development