Plant Defences Against Micro-Organism

Key Stage 4

Meaning

Plant defences against micro-organisms are the methods plants have to reduce the chance of infection and fight disease causing pathogens.

About Plant defences against micro-organisms

Plant defences against micro-organisms can be grouped into two main categories: Physical Barriers and Chemical Barriers.

Physical Barriers

• Waxy Cuticle - Leaves have a waxy cuticle which can prevent micro-organisms from entering the leaf.
• Bark - A layer of dead cells surrounds the outside of a tree trunk which blocks micro-organisms form getting into the stem.
• Cell Walls - The cell walls of individual cells can act as a barrier to viruses entering the cells.

Chemical Barriers

Plants produce a number of chemicals which have antiseptic or antibiotic properties.

When plants become distressed they give off pheromones which cause nearby plants to also produce antiseptic and antibiotic chemicals, preventing pathogens from spreading.