Nature of Association of Lichen - Symbiosis and Helotism

Lichens are organisms formed by the symbiotic association between algae and fungi that form a unique morphology distinct from both partner. The fungal partner is called mycobiont. The algal partner is called phycobiont.

Two views regarding the nature of association in lichen
1. Symbiosis: De Bary (1879) termed this association as symbiosis where both partners are benefitted
Justification: 
Advantages for algal partner or phycobiont:

• Algae get mechanical protection by fungal hyphal network
• Fungus absorbs more water and nutrients from the substratum, thus promoting algal growth

Advantages for fungal partner or mycobiont:

• Fungus gets nutrition from algae as algae is photosynthetic

2. Helotism: Crombic (1885) termed this association as ‘helotism’ a master- slave relationship where algae act as a slave for the fungal master.
Justification:

• Algae act as a slave and prepare food for the fungal master
• In some association, fungi produce haustoria like projections which penetrate the algae
• Algal sexual reproduction is inhibited by fungal association and adopted a slow growth under fungal influence.