Plant diseases and defences

• What is one sign of plant disease?

  Stunted growth
• What is another sign of plant disease?

  Spots on leaves
• What is a third sign of plant disease?

  Discolouration
• What is a fourth sign of plant disease?

  Patches of decay (rot)
• What is a fifth sign of plant disease?


  Malformed stems or leaves
• What is a sixth sign of plant disease?


  Abnormal growths, e.g. lumps
• What does seeing pests on a plant indicate?


  It is a sign of an infestation
• What are the types of pathogens that can infect plants?


  Viruses, bacteria, fungi
• What insect is mentioned as infesting plants?

  Aphids
• What effect does nitrate deficiency have on plants?


  It stunts growth
• Why are nitrate ions important for plants?


  They are needed to make proteins for growth
• What does magnesium deficiency cause in plants?


  Chlorosis (yellow leaves)
• Why are magnesium ions important for plants?


  They are needed to make chlorophyll
• What are the three ways to identify plant disease?

  1. Look up the signs in a gardening manual or website.
  2. Take the infected plant to a lab for identification.
  3. Use testing kits with monoclonal antibodies.
• What are the physical plant defences against pathogens?

  • Waxy cuticle on leaves
  • Layers of dead cells around stems (e.g. bark)
  • Cellulose cell walls
• What are the mechanical plant defences against herbivores?


  • Thorns and hairs to deter animals
  • Leaves that droop or curl to knock off insects
  • Mimicking other organisms to avoid being eaten
• What are the chemical plant defences against diseases?


  • Antibacterial chemicals that kill bacteria
  • Poisons produced to deter herbivores
• What are the main causes of plant disease?

  Microorganisms, insects, and deficiency diseases
• What types of microorganisms can cause plant diseases?

  Viruses, bacteria, and fungi
• What is a deficiency disease in plants?


  A condition caused by a lack of essential minerals
• What is the effect of nitrate deficiency in plants?


  It leads to stunted growth due to insufficient protein production
• What is the consequence of magnesium deficiency in plants?


  It results in chlorosis, which is yellowing of leaves
• What are some symptoms of plant disease?

  Abnormal growth, malformed stems/leaves, patches of decay, discoloration, and stunted growth
• How can you identify plant diseases?


  By looking up signs in gardening manuals or websites
• What is one method to identify pathogens in plants?


  Conducting a DNA test at a laboratory
• How can monoclonal antibodies be used in plant disease identification?


  They can identify pathogens through testing kits
• What is a physical defense mechanism in plants?


  Physical barriers like waxy cuticles and cellulose cell walls
• What is the function of a waxy cuticle on plant leaves and stems?


  It covers leaves and stems to prevent pathogen entry
• How do cellulose cell walls contribute to plant defense?


  They provide structural support and form layers of dead cells around stems
• What are chemical defenses that plants use against pathogens?


  Plants secrete antimicrobial substances and poisons to deter herbivores
• What is one way plants mechanically defend themselves?


  By having thorns or hairs to stop animals from eating them
• How do some plants respond when touched?

  Leaves may curl or droop to deter insects
• What is a strategy some plants use to avoid being eaten by animals?


  They mimic other organisms to confuse animals