Lichenes Course Materials

LICHENES (Lichen) This organism is actually a collection of fungi and algae, but in such a way that in terms of morphology and physiology it is one unit. trees, but can also be on the ground, especially in the tundra area around the north pole. We can find lichens on high mountains. Some types can penetrate the edges of rocks, therefore they are called endolithic. Lichens live as epiphytes on trees. Algae comes along Lichens make up the body , called gonidium, which can be single-celled or in the form of a colony. Most gonidium are blue algae (Cyanophyceae), including Choococcus and Nostoc, sometimes also green algae (Cholorophyceae), for example Cystococcus and Trentopohlia. Most of the fungi that make up Lichenes belong to the Ascomycetes , especially Discomycetales, only occasionally Pyrenomycetales. It is also possible that basidiomycetes take part in it form Lichenis. In pure kurtur, the fungus shows a morphological arrangement according to its type,but talus forms like Lichenes only occur if you encounter the right type of algae. Other algae will produce other lichens. So the shape of lichens depends on the type of way of life between the two types of organisms that make them up. It can also be considered that the relationship between the two algae of the fungus is helotism . The reciprocal benefits are only temporary, only at the beginning, but in the end the algae are manipulated by the fungus, and the relationship resembles that of a master and his slave (helot). In this case, living together between fungi and algae in Lichenes is called helotism. According to their habitus, we distinguish Lichenes whose thallus resembles sheets, like bushes. The first is usually attached with threads resembling rhizoids to the substrate on the entire underside of the thallus, while the second has a different tip of the thallus in the air. This division does not at all show the phylogenetic relationship between the members belonging to it. Most Lichenes reproduce vegetatively. In the thallus lichens the fungus can finally form fruit which according to the type of fungus can be an apothecium or perithecium. The spores released in a new place will develop into new lichens if they encounter the right type of algae, which is the same as the type of algae on the parent thallus. Lichenes are classified according to which fungus they arearrange it. Class ASCOLICHENES If the fungus that contains it belongs to Pyrenomycetales, then the fruiting body produced is in the form of perithesia, for example Dermatocarpon and Verrucaria. If the constituent fungi are classified as Discomycetales, Lichenes form fruiting bodies in the form of apothecium.In contrast to the free-living Discomycetales , whose apothecium is only short-lived, the apothecium in these Lichenes is long-lived, is cartilage-like and has a thick-walled ascus. This group includes Usnea (angina ribs) which form small bushes and are found in many trees in forests, especially in mountainous areas. Class BASIDIOLICHENES (HYMENOLICHENES) Most have talus in the form of sheets. In the fruiting body, a hymenium layer is formed containing a basidium, which closely resembles the fruiting body of Hymenomycatales. Example Cora pavonia. Lichenes were separated from fungi and made into an independent group. Most experts consider it necessary to separate lichens from fungi to form a separate group. So ithout algae, fungi generally can no longer survive and lichens will not form. Furthermore, considering the emergence of special properties and characteristics from the existence of symbiosis between Fungi and Algae , coupled with the obtaining of metabolic products which are substances that until now have not been produced by Fungi and Algae .Algae live separately so it is natural that Lichenes are a separate group.