B3 - Infection and Response

• Why do plants need nitrates?

  They make proteins for growth and repair
• Why do plants need magnesium ions?

  They make chlorophyll for photosynthesis
• Symptoms of magnesium deficiency

  Chlorosis (lack of chlorophyll)

  Yellow leaves
• Physical plant defences

  Dead cells around plants eg. Bark

  Cellulose cell walls

  Waxy cuticles on leaves and stems
• Symptoms of nitrate deficiency

  Stunted growth
• Chemical plant defences

  Antimicrobials (kill bacteria)

  Toxins/ Poisons (kill or ward off insects)
• Mechanical plantplant defences

  Thorns/Hairs that ward off animals

  Leaves that droop if insects go on them