Chemical Growth Regulation

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Chapter 12

• Chemical Growth Regulation

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Chemicals ThatControl Growth

• Naturally Occuring
• Hormones
• Synthetically produced
• Plant Growth Regulators (PGR)

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HORMONES

• 1. Auxins - promote growth primarily through cell
  enlargement in localized areas
• Hormone IAA (Indoleacetic Acid)
• PGR IBA, IPA, NAA
• 2. Gibberellic Acid (GA) - promotes growth
  through cell enlargement throught plant tissues
• 30 to 40 different GAs naturally occuring and
  synthetic

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HORMONES

• 3. Cytokinins - promote growth through cell
  division (AKA juvenility hormone)
• Used primarily in plant tissue culture
• Ex various types of compounds resembling
  benzyladenine
• 4. Ethylene - has numerous effects includung
  fruit ripening, flower stimulator, color
  development, senescence promoter, etc.
• (is a gas)

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HORMONES

• 5. Abscisic Acid - retards growth, promotes
  abscission of leaves and flower petals
• Is known as the senescence hormone

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Plant Growth Regulators

• Florel - produces ethylene
• Cycocel (CCC) - growth retardant
• Works as an anti-gibberellin
• B-Nine (Alar) - growth retardant
• A-Rest - growth retardant
• Off-Shoot-O - chemical pinching agent
• Kills terminal bud
• Atrinal - stops shoot elongation, increases
  lateral branching (removes apical dominance)