Symbiotic Relationship
The relationship between fungus and photobiont is often described as:
- Mutualistic — both partners benefit
- Controlled parasitism — the fungus controls growth and environment
- Obligate dependence — many lichens cannot survive without their specific partners
The fungus provides:
- Structure
- Moisture retention
- Mineral absorption
- Protection from UV and desiccation
The photobiont provides:
- Carbohydrates via photosynthesis
- Nitrogen (if cyanobacteria are present)
Together, they form a single, stable ecological unit.