Write a detailed note on Fungi?
In rainy seasons we see tangled threads like structures with black dots of molds
growing on oranges and bread. These mushrooms and molds are Fungi. Fungi are
simple heterotrophic eukaryotes.
Nutrition: -
They cannot prepare their own food. On the basis of nutrition fungi has two types: -
i) Parasites: Some fungi are parasites. They obtain their food from other living
organisms (hosts). Many of them cause disease in man, animals and in crops.
ii) Saprotrophs: They get their food from dead organisms. Mushrooms and bread
mold Rhizopus are saprophytic fungi.
Structure: -
i) Its cell wall is made up of chitin which is a complex carbohydrate.
ii) Body of fungus is composed of branched, tubular thread called hyphae.
iii) A group of hyphae is called mycelium.
iv) Hyphae may be septate or non-septate. Septate hyphae have partitions
called septa which divide the hyphae into cell like chambers. Each chamber
contain one or more nucleus.
v) Non Septate hyphae lack septa and contain many nucleuses in cytoplasm.
They are also called coenocytic hyphae.
Reproduction: -
In the presence of suitable conditions, fungi spread rapidly by means of spores. Fungi
directly reproduce sexually as well as asexually.
Classification of Fungi: -
There are approximately one lakh known species of fungi. These are classified on the
basis of structure of sporangium, methods of spore formation and characteristics of
mycelium.
Groups of Fungi: -
There are four large groups of fungi.
i) Zygomycetes (For example Rhizopus)
ii) Ascomycetes or sac fungi (For example Morels and Yeasts)
iii) Basidiomycetes (For example rust, mushrooms)
iv) Imperfect fungi (For example Alternaria)