All about Lichens

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"All about Lichens"
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Lichen is an example of a symbiotic relationship between two or more species where each partner gains something from the other. In the case of lichens, the organisms involved include a fungus, a cyanobacterium and algae. However, it is possible for lichens to have only two organisms although the dominant partner in any combination is the fungus. The symbiotic relationship existing between the partners within lichen makes them extremely resistant to environmental hazards, except for air pollution to which it is extremely sensitive. This article will discuss the features of lichens including how it reproduces, where it occurs, its survival ability, as well as the various uses of lichens in modern day practices.

What is the structure of lichens?

When lichens are formed, it is arranged in such a way that the algae and the cyanobacteria are sandwiched between layers of fungal tissue. This would make cyanobacteria and algae protected from harsh sunlight and extreme temperatures as well as from windy conditions and droughts. This makes the algae to live in environments, which would otherwise destroy the organism without a doubt. At the same time, the enclosed cyanobacterium and the algae can produce carbohydrates using the filtered out sunlight that they receive and this would be the food source utilized by the fungus for its survival. Thus, without each other’s help, these organisms would not be able to tolerate the harsh conditions that they endure.

How do lichens reproduce?

Lichens have shown to have two methods of reproduction and these include the formation and dissemination of spores by the fungal partner, or by forming structures known as soredia. In the first instance, if the spores contain algae or cyanobacteria, it is possible for a new lichen to form after the spores alight to germinate. However, in the absence of algae or cyanobacteria, the fungus may soon die. In the second method, soredia would be able to form lichens in a more consistent manner because it contains both fungal and algae material within the same structure. The reproducing structures of lichens are usually disseminated through wind, animals or through rain.

What are the common locations where lichens form?

Lichens can be seen in harshest environments in the world and among them arctic tundra, hot deserts and rocky coasts are some of the highlights. However, lichens find themselves attached to the leaves and branches of trees in the rainforest, as well as on temperate woodlands or else on the surfaces of bare rock, on walls as well as on gravestones. Such adaptability also emphasizes the effectiveness of the symbiotic relationship existing within the lichens.

What are its different uses?

Humans have used lichens for many centuries; some of its earliest uses were for producing dyes and pigments for paintings and coloring various items. From ancient times, lichens played a role in traditional medicine in the form of teas and salves, while in the modern medicine it is included in some of the antibiotic creams. Furthermore, lichens have been used for monitoring air pollution, because it is a highly sensitive structure, which diminishes with the increasing levels of pollution. At the same time, archeologists has used lichens for dating soils and other objects based on the presence of lichens. The reason for using lichens for dating archeological sites or objects is its ability to live on such surfaces for a longer period of time.

Thus, when considering the above facts, it is apparent that lichens need to be protected and one of the main steps towards protecting lichens would be to minimize the air pollution that threatens even the hardiest of all living things.

More about this author: Dr Pandula Siribaddana

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