Plant Hormones

• Plant hormones, also known as phytohomones, are chemicals produced by plants to regulate their growth, development, reproductive processes, longevity, and even death.
• 7 major kinds of plant hormones

  • auxin
  • cytokinin
  • gibberellic acid
  • abscisic acid
  • ethylene
  • brassinosteroids
  • oligosaccharins
• Auxin

  • produced in the apical regions of the plant
  • growth hormone
  • promotes cell elongation
  • important in phototropism
• Phototropism is the ability of the plant to direct the shoot growth towards the direction of a light source.
• Cytokinin

  • cytokinin and auxin work together to promote cell growth
  • responsible for creating new cells in plants
  • causes branching to happen in plants
  • produced in cells that are actively growing
  • promotes cytokinesis (cytoplasm division after meiosis/ mitosis)
  • bud formation
• Gibberellic Acid

  • growth hormone
  • also known as gibberellin
  • produced in the root and shoot apices, young leaves, and seeds.
  • promotes stem and fruit elongation
  • enzyme production and germinating seeds
  • restores normal growth and development of dwarf mutant plants
• Abscisic Acid

  • a hormone that signals dehydration
  • synthesized in the chloroplast of the leaves
  • involved with leaf and fruit abscission
  • ensure that the stomata of the leaves stay close during drought season
  • inhibits cell germination and development
• Ethylene

  • ripening hormone
  • usually found in gaseous form
  • ripens fruit
  • important in germinating plants
• Brassinosteroids

  • similar to plant hormones like cortisol and testosterone which are steroid hormones
  • their effects include cell division, elongation, bonding and delayed senescence
• Oligosaccharins

  • abundant in a cell wall of plants
  • there are said to affect the signal defense responses of plants