Plant disease and responses

• We can diagnose diseases in plants by looking for insects such as aphids, discoloration spots on leaves, stunted growth, decay or abnormal growths, and malformed stems or leaves
• Ways to identify plant diseases

  1. Use a garden manual or website

  2. Take the infected plant to a lab to identify the pathogen

  3. Use testing kits containing monoclonal antibodies
• Plant ion deficiency diseases

  Plant diseases not caused by pathogens
• A lack of the nitrate ion causes stunted growth because nitrate is needed for protein synthesis and therefore growth
• A lack of the magnesium ion causes chlorosis because magnesium is required to make chlorophyll, causing the leaves to lose their green coloration
• We can diagnose diseases in plants by looking for insects such as aphids, discoloration spots on leaves, stunted growth, decay or abnormal growths, and malformed stems or leaves
• Ways to identify plant diseases

  1. Use a garden manual or website

  2. Take the infected plant to a lab to identify the pathogen

  3. Use testing kits containing monoclonal antibodies
• Plant ion deficiency diseases

  Plant diseases not caused by pathogens
• A lack of the nitrate ion causes stunted growth because nitrate is needed for protein synthesis and therefore growth
• A lack of the magnesium ion causes chlorosis because magnesium is required to make chlorophyll, causing the leaves to lose their green coloration
• Plant defense systems against attack

  • Physical responses
  • Chemical responses
  • Mechanical responses
• Physical responses

  • Cellulose cell wall difficult for microorganisms to penetrate
  • Waxy cuticle on leaves difficult for microorganisms to penetrate
  • Layers of dead cells around stems (bark) as a barrier to entry for microorganisms
• Chemical responses

  • Plants release antibacterial chemicals to kill bacteria and prevent them attacking the plant
  • Plants release poisons to deter herbivores from grazing on the plant
• Mechanical defense system

  • Thorns or hairs that directly protect the plant from being eaten by herbivores
  • Leaves that droop or curl when touched, which may scare herbivores
  • Mimicry, where a plant looks similar to a stinging nettle but has no sting, deterring herbivores