HORMONES

• PLANT HORMONES

  • Auxin
  • Cytokinin
  • Gibberellic Acid
  • Abscisic Acid
  • Ethylene
• Auxins

  
  

  synthesized in shoot apical meristems, young leaves, seeds and fruits
• Auxins

  
  

  • promote growth in molar concentrations of 10^-3 to 10^-8
• Auxins

  
  

  ____ produced in apical buds - inhibit the activation of buds lower on the stems (apical dominance)
• Auxins

  
  

  Promote lateral and adventitious root development
• Auxins

  
  

  Fruit development requires ____ produced by the developing seed.
• Auxin

  
  

  ____ pastes applied to developing ovaries can promote parthenocarpy (fruit development in the absence of fertilization)
• Auxins

  
  

  toxic in large concentrations
• Auxins

  
  

  affect mostly dicots but not monocots
• Auxins

  
  

  Monocots seem to be able to rapidly degrade the synthetic ____
• Auxins

  
  

  Synthetic ____ herbicides include 2-4-D and 2-4-5-T (Agent orange of the Vietnam era contains synthetic auxin)
• Auxins

  
  

  Used as defoliants
• Auxins

  
  

  Used as weed killers
• Cytokinin

  
  

  phenyl urea derivatives of adenine, one of the molecules in DNA
• Cytokinin

  
  

  found in actively dividing tissues of seeds, fruits, leaves and root tips, and wound tissue sites
• Cytokinin

  
  

  transported through xylem to the rest of the plant
• Auxins

  
  

  which promote elongation and cell expansion
• Cytokinin

  
  

  promote axillary/lateral bud growth by over-riding the apparent inhibiting effect of auxin
• Gibberellic Acid

  
  

  Many seeds contain a variety of different ______ Over 100 different _______ (organic acids synthesized from mevalonic acid)
• Gibberellins

  
  

  are produced in roots and younger leaves, with seeds having the highest concentration
• Gibberellins

  
  

  Most effects of _____ are shown only in concert with auxins
• Gibberellins

  
  

  Reversal of genetic dwarfism GA
• Gibberellins

  
  

  Bolting of biennials, to produce flowers during the first growing season
• Gibberellins

  
  

  _____ like auxins, promote parthenocarpy
• Abscisic Acid

  
  

  inhibits growth activities in times of environmental stress rather than by promoting growth
• Abscisic Acid

  
  

  often serves as an antagonist to the other growth promoting hormones in plants.
• Abscisic Acid

  
  

  _____ promotes seed dormancy
• Abscisic Acid

  
  

  Low levels of _____ in maturing seeds promote premature germination
• Abscisic Acid

  
  

  _____ is also referred to as the stress activity hormone
• Abscisic Acid

  
  

  _____ promotes stomata closure during leaf water deficit conditions by activating K+ ion transport out guard cells
• Ethylene

  
  

  synthesized from the amino acid methionine
• Ethylene

  synthesized from the amino acid methionine
• Ethylene

  Promotes flowering
• Ethylene

  promotes leaf senescense