Plants disease and Defences

Where do plants get mineral ions from?

Soil

What happens to plants when they don't get enough mineral ions?

They suffer deficiency symptoms

What are nitrates needed for?

Making proteins -> growth

What are mineral ions containing (as a subheading)?

Nitrates and Magnesium ions

What does a lack of nitrates cause?

Stunted growth

What are magnesium ions needed for?

Making chlorophyll

Why do plants need chlorphyll?

Needed for photosynthesis

What do plants without magnesium ions suffer from?

Chlorosis and have yellow leaves

What are the 6 common signs that a plant has a disease?

• Stunted growth
• Spots on the leaves
• Patches of Decay (rot)
• Abnormal growths
• Malformed stems or leaves
• Discolouration

How do you identify different plant diseases?

• Looking up signs in a gardening manual or website
• Taking the infected plant to a lab, scientists identify the pathogens
• Using testing kits that identify the pathogen using monoclonal antibodies

What are the physical plant defences?

• Waxy cuticle
• Cell Walls
• Layers of dead cells

How do plants use a waxy cuticle (physical) do defend against disease?

Provides a barrier to stop pathogens entering

How do plants use cell walls (physical) do defend against disease?

Form a physical barrier against pathogens that make it past the waxy cuticle

What are cell walls made from?

Cellulose

How do plants use layers of dead cells (physical) do defend against disease?

Dead cells around their stems e.g., bark on trees

What are the chemical plant defences?

• antibacterial chemicals
• poisons

How do plants use an antibacterial chemicals (chemical) do defend against disease?

These kill bacteria e.g., mint and witch hazel

How do plants use poisons (chemical) do defend against disease?

Deter herbivores e.g., tobacco plants, foxgloves, deadly nightshade

What are the mechanical plant defences?

• thorns and hairs
• leaves which droop or curl
• mimicking

How do plants use thorns and hairs (mechanical) do defend against disease?

Stops animals touching and eating them

How do plants use leaves drooping (mechanical) do defend against disease?

Prevent themselves being eaten by knocking infected off themselves and moving away from things

How do plants use mimicking (mechanical) do defend against disease?

e.g., the Passion flower has bright yellow spots on its leaves which look like butterfly eggs. This stops butterflies laying their eggs on there