Lichens: Algae and Fungus

Lichens are unique organisms that are formed through a symbiotic relationship between algae or cyanobacteria (referred to as the photobiont) and fungi (referred to as the mycobiont). This symbiosis is so intimate that they are often considered as a single entity. Here is a detailed explanation of lichens, their components, and their symbiotic relationship.

Components of Lichens
Lichens consist of two main components:

1. Algae or Cyanobacteria (Photobiont):
- Algae or cyanobacteria are microorganisms capable of photosynthesis.
- They provide food (carbohydrates) to the lichen through photosynthesis.
- The most common photobionts found in lichens are green algae and cyanobacteria.

2. Fungi (Mycobiont):
- Fungi belong to the kingdom Fungi and provide protection and structural support to the lichen.
- They absorb water and minerals from the environment for the lichen.
- The mycobiont is usually an ascomycete, but it can also be a basidiomycete or a few other fungal groups.

Symbiotic Relationship
The symbiotic relationship between algae or cyanobacteria and fungi in lichens is mutualistic, benefiting both organisms. The key aspects of this relationship are as follows:

1. Protection and Structure:
- The mycobiont provides a protective and supportive structure to the photobiont.
- It forms a network of fungal hyphae around the photobiont, creating a unique structure called the thallus.

2. Photosynthesis and Food:
- The photobiont carries out photosynthesis, producing carbohydrates.
- These carbohydrates are shared with the mycobiont, which lacks the ability to perform photosynthesis.
- In return, the mycobiont provides minerals and water absorbed from the environment to the photobiont.

Benefits of the Symbiotic Relationship
The symbiotic relationship between algae or cyanobacteria and fungi in lichens offers several advantages, such as:

1. Survival in Extreme Environments:
- Lichens are incredibly resilient and can survive in harsh environments like deserts, rocky habitats, and tundras.
- The combined effort of the photobiont and mycobiont allows lichens to tolerate extreme temperatures, drought, and high radiation levels.

2. Increased Nutrient Availability:
- The mycobiont enhances nutrient availability by breaking down organic matter, making nutrients accessible to the lichen.
- Lichens can grow in nutrient-poor environments due to the mycobiont's ability to extract nutrients from various sources.

3. Environmental Indicators:
- Lichens are used as bioindicators to assess air quality and pollution levels.
- They are sensitive to air pollutants and changes in environmental conditions, making them excellent indicators of ecosystem health.

In conclusion, lichens are fascinating organisms resulting from the symbiotic relationship between algae or cyanobacteria and fungi. This partnership allows them to

It is an mutal association between alege and fungi this is called lichen. This is known as symbiosis relationship.