Plant responses to abiotic stress

• Abiotic stresses

  • Soil pH
  • Very high or low temperature
  • Lack or excess water
  • High wind
  • Low light intensity
  • Lack of minerals
• Leaf abscission

  = Falling light levels result in falling concentrations of auxin.

  • The leaves respond to falling auxin concentrations by producing ethene.
  • Ethene initiates genes switching producing enzymes.
  • They digest and weaken cell walls in the abscission zone.
  • Vascular bundle is sealed off.
• Stomatal closing

  Due to increased temperature and low water availability.

  • ABA reduces water potential and turgor of cells so guard cells close stomata.
• Anti-freeze molecules

  • Lower freezing point of water in plant.