B3 - Plant Diseases and Defences

How does a deficiency of nitrates affect a plant?

Stunt in growth.

How does a deficiency of magnesium ions affect a plant?

Less photosynthesis so they suffer from chlorosis and have yellow leaves.

What are the symptoms of plant diseases?

Stunted growth, abnormal growths, spots on leaves, malformed stems or leaves, patches of decay and discolouration.

How can plant diseases be identified?

Looking up signs on a garden manual or website, taking the plant to a laboratory where scientists can identify the pathogen, or by using test kits that identify the pathogen using monoclonal antibodies.

What physical defences do plants have against disease?

Waxy cuticle acts as a barrier